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Date: 22 Nov 92 03:23:00 EST
From: INFO-UNIX@BRL.MIL
Subject: INFO-UNIX Digest  V17#010
To: "DGRAY" <DGRAY@STARLAB.CSC.COM>

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From:       The Moderator (Mike Muuss) <Info-Unix-Request@BRL.MIL>
To:         INFO-UNIX@BRL.MIL
Reply-To:   INFO-UNIX@BRL.MIL
Subject:    INFO-UNIX Digest  V17#010

INFO-UNIX Digest          Sat, 21 Nov 1992              V17#010

Today's Topics:
                         SCCS to RCS Conversion
                        Re: IS UNIX DEAD (long)
                        Passing args to login(1)
                      Re: Passing args to login(1)
               using the floppy drive on a sparcstation?
             Re: using the floppy drive on a sparcstation?
                how do I know on which console I work ?
              Re: how do I know on which console I work ?
                     Re: pwd: getwd: can't open ..?
             Re: Looking for Time Series Analysis software
                       PostScript output from man
              Mixing Unix 120& Novell on the same network?
                 Re: Any terminfo compilers available?
              Re: How do I increase number of screen rows?
                         Re: Internet question
                                awk info
                        Re: Unattended execution
                       Re: What's HP Boat Format
                     Re: Absurd! (Re: IS UNIX DEAD)
             Re: It ain't a 24x80 world anymore. Or is it?
              Re: How does a mortal become a UNIX WIZARD ?
                        Re: IS UNIX DEAD? (long)
                     Re: IS UNIX DEAD? (very long)
                 Re: Recursive Tree Copy (with filter)?
                           LaTeX Compilation
           Welcome to comp.unix.questions [Biweekly posting]
    Frequently Asked Questions about Unix (index) [Biweekly posting]
     Frequently Asked Questions about Unix (1/7) [Biweekly posting]
     Frequently Asked Questions about Unix (2/7) [Biweekly posting]
     Frequently Asked Questions about Unix (4/7) [Biweekly posting]
     Frequently Asked Questions about Unix (3/7) [Biweekly posting]
     Frequently Asked Questions about Unix (5/7) [Biweekly posting]
     Frequently Asked Questions about Unix (7/7) [Biweekly posting]
     Frequently Asked Questions about Unix (6/7) [Biweekly posting]
                    Re: What's wrong with select() ?
                  Loking for a code for GIBBS SAMPLER
                        general unix info needed
  make, makefile where s.'s are in another directory, clean solution ?
                    text search software(follow-up)
      Utility for keeping two directories consistent (identical)?
                                Re: grep
-----------------------------------------------------------------

From: "Fred J. Sena" <fjs@mrst.uucp>
Subject: SCCS to RCS Conversion
Date: 17 Nov 92 23:26:53 GMT
Followup-To: comp.unix.programmer
To:       info-unix@sem.brl.mil

hi,

I want to convert a bunch of source files from SCCS to RCS.  I have a tool
called "sccstorcs" that came out around 1982, but I tried it on some files
and it broke (on some branches, I think).  I would try and fix it, but first
I thought that it would be a good idea to see if there is another version
available.

I hope that there is a more up-to-date version available, that presumably
would have this fixed.  If you have any information or know where I can
obtain a good copy, I would really appreciate hearing from you.  Please
email if possible, and I will post a summary to all of those who are
interested.

	thanks,
	-fred

-----------------------------

From: Peter Busser <peter@global.hacktic.nl>
Subject: Re: IS UNIX DEAD (long)
Date: 18 Nov 92 11:49:21 GMT
To:       info-unix@sem.brl.mil

andy@research.canon.oz.au (Andy Newman) writes:

>papresco@napier.uwaterloo.ca (Paul Prescod) writes:

>>True, the problem is there are people, in this very newsgroup, who see
>>no reason to try to make user friendly applications for unix.  To them,
>>if you can't use VI right off the bat, or enjoy learning obscure, 
>>nonsensical, illogical keystrokes, you should go back to the mac.
>>THIS will kill Unix.

>Define "user friendly". Aren't the people who like vi users too?

Of course they are. But there are also easy to use editors availlable for X
such as textedit (from the XView3 library) and aXe. The problem is that such
an editor are not always delivered with a system and people are stuck to vi
or emacs.

Greetings,
Peter Busser

-----------------------------

From: Superuser <root@shiptile.chi.il.us>
Subject: Re: IS UNIX DEAD (long)
Date: 18 Nov 92 14:59:15 GMT
To:       info-unix@sem.brl.mil

>True, the problem is there are people, in this very newsgroup, who see
>no reason to try to make user friendly applications for unix.  To them,
>if you can't use VI right off the bat, or enjoy learning obscure, 
>nonsensical, illogical keystrokes, you should go back to the mac.
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

I don't understand why you would say this.  Most UNIX users (myself included)
would consider UNIX keystrokes to be as sensible and logical as any other.
Not meaning to offend the writer, but does (s)he use UNIX?

>THIS will kill Unix.

I doubt it.

-----------------------------

From: George Jetson <pynq@quads.uchicago.edu>
Subject: Passing args to login(1)
Date: 18 Nov 92 14:58:21 GMT
To:       info-unix@sem.brl.mil

I am pretty sure that under at least some versions of Unix/login, you can
pass args in along with your login-id, and that these args would then be
available to your .login/.profile.  See below:

	login: pynq and green
	Password: 

	Then $1 should be "and" and $2 should be "green".

However, this doesn't seem to work under my current version of login
(and version of SunOS [4.something])

So, my question is: "Am I imagining things, or am I doing it wrong?"

I could of course ask questions in the login script and branch
accordingly, but it would be cleaner to be able to do it as a command
line parameter.

************************************************************************
I've been told to back off on the diode jokes, but I still don't
like smileys ;-)

	- pynq@quads.uchicago.edu, who is still costing the net
	  hundreds, if not thousands, of dollars, every time he posts -
************************************************************************

-----------------------------

From: Clarence Dold <dold@unislc.uucp>
Subject: Re: Passing args to login(1)
Date: 19 Nov 92 03:23:34 GMT
To:       info-unix@sem.brl.mil

From article <92323.143304AASSI@CUNYVM.BITNET>, by abraham <AASSI@CUNYVM.BITNET>:
>> From: pynq@quads.uchicago.edu (George Jetson)
>> Subject: Passing args to login(1)
>> Date: Wed, 18 Nov 1992 14:58:21 GMT
>>
>> I am pretty sure that under at least some versions of Unix/login, you can
>> pass args in along with your login-id, and that these args would then be
>> available to your .login/.profile.  See below:
>>
>>         login: pynq and green
>>         Password:
>>
>>         Then $1 should be "and" and $2 should be "green".

Close.  The arguments are $L0="and", $L1="green", which you should have
noticed, when you did an "env" after login.

However, I find that this isn't supported on all of the systems I tried, but
it is on both SVR3.2 and SVR4 variants.

Check your "man login" to see if it is available. My SVR4:
"          either the form xxx or xxx=yyy. Arguments without an equals
"          sign are placed in the environment as
"               Ln=xxx
"          where n is a number starting at 0 and is incremented each

-- 
---
Clarence A Dold - dold@unislc.slc.Unisys.COM
               ...pyramid!ctnews!tsmiti!dold

-----------------------------

From: Shane Hutchins aka Xenos <sch@nymph.msel.unh.edu>
Subject: using the floppy drive on a sparcstation?
Date: 18 Nov 92 15:04:01 GMT
NNTP-Posting-Host: nymph.msel.unh.edu
To:       info-unix@sem.brl.mil

I'd like allow users to transfer files from the floppy drive on our
Sun4 SPARCstation IPCs to their account.         (/dev/fd0)

Unfortunately, it requires root permissions to mount the thing.

Is there some freeware out there that will allow a user to mount /pcfs
and eject (ie use the damn floppy drive) without root access.

Thanks for your help...
-- 
  -Shane C Hutchins
     sch@unh.edu

-----------------------------

From: Clark Burdick <clark@gopher.stanford.edu>
Subject: Re: using the floppy drive on a sparcstation?
Date: 19 Nov 92 16:35:51 GMT
To:       info-unix@sem.brl.mil

In article <1edm11INNoom@mozz.unh.edu> sch@nymph.msel.unh.edu (Shane Hutchins aka Xenos) writes:
>I'd like allow users to transfer files from the floppy drive on our
>Sun4 SPARCstation IPCs to their account.         (/dev/fd0)
>
>Unfortunately, it requires root permissions to mount the thing.
>
>Is there some freeware out there that will allow a user to mount /pcfs
>and eject (ie use the damn floppy drive) without root access.
>
>Thanks for your help...
>-- 
>  -Shane C Hutchins
>     sch@unh.edu


The program usermount is available from guardian.cs.psu.edu in the
directory /pub/src for anonymous ftp. This program is very easy to install
and allows users to mount floppy disks and cd-roms without root access.

Hope this helps,
Clark Burdick

-----------------------------

From: errera alfred <errera@shum.cc.huji.ac.il>
Subject: how do I know on which console I work ?
Date: 18 Nov 92 15:53:03 GMT
To:       info-unix@sem.brl.mil

Hello.
We have a system of some SPARC 1 & 2 and some sun386i used as X terminal.
We do a lot of rlogin from one machine to another .
My question is : how do I know what is the console I work on?
namely how do I know the right setting for the DISPLAY variable so that
X programs will run on my display even when I do rlogin ?
please email or post the answer.
thanks a lot.
Eliel
errera@shum.cc.huji.ac.il

-----------------------------

From: Michael Salmon <etxmesa@eos.ericsson.se>
Subject: Re: how do I know on which console I work ?
Date: 19 Nov 92 09:41:05 GMT
To:       info-unix@sem.brl.mil

In article <1992Nov18.155304.736@vms.huji.ac.il>, errera@shum.cc.huji.ac.il (errera alfred) writes:
|> Hello.
|> We have a system of some SPARC 1 & 2 and some sun386i used as X terminal.
|> We do a lot of rlogin from one machine to another .
|> My question is : how do I know what is the console I work on?
|> namely how do I know the right setting for the DISPLAY variable so that
|> X programs will run on my display even when I do rlogin ?
|> please email or post the answer.
|> thanks a lot.
|> Eliel
|> errera@shum.cc.huji.ac.il

This is a repost. I have since used this technique very successfully.
There is a catch though. Some systems only store the first 16
characters of the remote sites name and that can cause a problem.

In article <3842@bimacs.BITNET> 
yedidya@bimacs.BITNET (Yedidya Israel) writes:
>
>Hello net.
>
>Can I get help with writing a script that will define my DISPLAY
>environment variable from .cshrc according to the environment I
>telnetted/rlogined from.
>
>I.e. if I telnet from a regular terminal (say vt100) then do not
>define $DISPLAY at all. If I telnet from an xterm or dxterm or aixterm
>X environments define my $DISPLAY to the existing one (if exists) or
>derive it from who am i.

On our Apollo (BSD) systems I do:

set host = `hostname`
#
# Set the default X Windows server name - set to the name of the host
# the user logged in from, unless it was the terminal server (tserver).
# Also strip off the local domain name (.chem.utoronto.ca) if possible.
#
setenv DISPLAY "${host}:0"
set displayhost=`who am i | sed -e 's/.*(//' -e 's/).*$//' -e 's/\.chem\.utoronto\.ca$//'`
if ("$#displayhost" == "1") then
   if ("$displayhost" != "tserver") then
      setenv DISPLAY $displayhost\:0
   endif
endif
unset displayhost

and on our HP (SYSV-sortof) systems I do:

set host = `hostname`
#
# Set the default X Windows server name - set to the name of the host
# the user logged in from, unless it was the terminal server (tserver).
# Also strip off the local domain name (.chem.utoronto.ca) if possible.
#
setenv DISPLAY "${host}:0"
tty -s
if ("$status" == "0") then
   set displayhost=`who am i -R | sed -e 's/.*(//' -e 's/).*$//' -e 's/\.chem\.utoronto\.ca$//'`
   if ("$#displayhost" == "1") then
      if ("$displayhost" != "tserver") then
         setenv DISPLAY $displayhost\:0
      endif
   endif
   unset displayhost
endif

You will have to surround this with code to only do it for $TERM types
you want. You'll just have to trust the user hasn't messed with $TERM;
if the wrong $TERM is propagated from the remote system, tough luck for
the user. It is possible to send some messages to some terminals
and check the response (this works for vt100/xterm) so that might be
a way to check out the terminal type.
-- 
What are the chances that any computer system will ever "work" properly?
 ... and Slim just left town. -*- Mike Peterson, SysAdmin, U/Toronto Chemistry

-- 

Michael Salmon

#include	<standard.disclaimer>
#include	<witty.saying>
#include	<fancy.pseudo.graphics>

Ericsson Telecom AB
Stockholm

-----------------------------

From: Art Dyer <ahd@apollo.sunquest.com>
Subject: Re: pwd: getwd: can't open ..?
Date: 18 Nov 92 16:31:28 GMT
To:       info-unix@sem.brl.mil

In article <Bxt31B.4Fn@uiag.ch> jonas@uiag.ch (Jonas Furrer) writes:
>Hi,
>
>why I have this error -> pwd: getwd: can't open ..
>
> [...]

When I had this problem, it was because of the mode of the mount point
(which you cannot see while the filesystem is mounted).  Unmount the
filesystem and _then_ examine the mode of /files/disk2/imagery.
--
Art Dyer    ahd@apollo.sunquest.com    Voice:  (602) 570-2000

-----------------------------

From: "Stephen e. Rhody" <serhody@rodan.acs.syr.edu>
Subject: Re: Looking for Time Series Analysis software
Date: 18 Nov 92 16:56:48 GMT
To:       info-unix@sem.brl.mil

In article <1992Nov17.051627.10815@midway.uchicago.edu> sjs6@midway.uchicago.edu writes:
>
>The leading program for time series analysis is probably RATS, which runs
>under DOS, the Macintosh, Unix and perhaps some other operating systems
>as well.
>
>The company that writes this is located in Evanston, IL.  Their name used
>to be VAR econometrics, but they might well have changed it about a year ago
>(perhaps to "Estima", but I could have them confused with another company).
>
>RATS stands for something like "regression analysis for time series" and 
>contains a broad array of time series analysis functions including specral
>analysis.
>
>If you cant track this down yourself, contact me by email and I will send
>you the phone number.
>
>-- 
>Jonathan Silverman
>
>sjs6@quads.uchicago.edu
>jonat@cicero.spc.uchicago.edu


From the RATS 4.0 manual:

Rats is produced by

Estima 1800 Sherman Ave., Suite 612
Evanston, IL 60201

Phone Numbers:

(708) 864-8772	(General Information)
(708) 864-1910	(Technical Support:  9am-5pm Central time)
(708) 864-6221	(Fax)
(708) 864-8816	(Bulletin Board)

Hope this helps

Steve

-----------------------------

From: Barbara Vaughan <bvaughan@sheps.princeton.edu>
Subject: PostScript output from man
Date: 18 Nov 92 20:16:27 GMT
Originator: news@nimaster
To:       info-unix@sem.brl.mil

Can someone suggest a way of either getting PostScript output for a man
page or finding the fully qualified path name for a man page.  Here is
some background:

We have a PostScript printer (HP Laserjet 3si) that lets us print on both
sides of a page using PostScript commands.  (About four lines of
PostScript headers have to be prepended to an existing PostScript file.)  I
have figured out how to
implement this for everything but man pages.  If it's a TeX file, I use
dvips to convert it to PostScript, if a plain text file, I use enscript. I've
written a shell script that figures out what kind of file you have and
that has a -d (for "duplex") command line switch so that even our most
novice users can save paper, and I'd like to make a similar shell script
for man pages so that you can say "manprint -d _command_" and you'll get a
duplex-printed man page.  (Or maybe I could add a "-man" command line
switch to my existing script.)  At any rate, I need PostScript output from
the man page.

I've tried the following:

man -t _command_ >tempfile
pscat tempfile 

(pscat fails and dumps core; this seems to be a pscat bug)

I have found that if I know the name of the man page file, I can use
ptroff -t -man _man.page.file.name_ to produce a PostScript version of the
man page, but our man pages reside on many different directories, so I
would like a way to have my shell script identify the path/name of the file
where the man page resides, so the user doesn't have to know this in advance.

I've also tried various ways of piping output of man directly to ptroff,
This also fails, even if I set my TROFF environment variable to PTROFF. 
The closest I get is a PostScript file containing nothing but headers and
status dictionary, font definitions, etc.

Thanks for any help you can give,

Barbara Vaughan

-----------------------------

From: Kenneth Leung <allanon@sdf.lonestar.org>
Subject: Mixing Unix \w TCPIP & Novell on the same network?
Date: 18 Nov 92 21:27:43 GMT
To:       info-unix@sem.brl.mil

I have a question about mixing Novell servers & Unix Servers on the same
network.

Configuration : 1 SUN Sparc Server, 10 SCO Unix servers, 20 DOS PCs running
		different TCP/IP Software such as FTP Software's PCTCP,
		SUN NFS, ICE TCP & Chameleon TCP, over a Cabletron Ethernet
		network.  The DOS PC runs telnet to different Unix machines
		for different applications such as accounting or product
		development.


Now Management wants to put a Novell server in to the network and allow DOS
users to access both Unix resources and Novell resources.  I am not too 
familiar with Novell and how to mix it in with the TCP/IP network I am 
currently running.  

Can I run dual protocols on the DOS PC to access both Unix and Novell?
Can I use Unix or Novell to gateway between one another?  Any
info would be helpful.

Thanks in advance.


-- 
 -------------------------------------------------------------------------------
Kenneth C.P. Leung      /Sweda Division       --  Point of Sales Systems Co.
Innovax Concepts Corp.  \Outsourcing Division --  Systems Planning & Consulting
1303 Walnut Hill Ln. 2nd Floor Irving TX 75038   Tel. 214-550-8371 x6828

-----------------------------

From: Ade Barkah <mbarkah@slate.mines.colorado.edu>
Subject: Re: Any terminfo compilers available?
Date: 19 Nov 92 00:40:20 GMT
To:       info-unix@sem.brl.mil

bhays@teal.csn.org (Boyd Hays) writes:
:     I need to write a program that parses terminfo source files. There was
:     something available about 5 years ago, a small lex scanner, but I can't
:     find it anywhere.

I'm not sure about where to find it, but since most Unices come with 
the 'tic(1)' command, I'd say look at the free Unix directories
(like linux or 386bsd) for the sources to tic.

I think GNU has a terminfo package, too... so you may want to
grab it from your local ftp site and canniballize the source
code (unless you're going to use it commercially, that is.)

Other than that, maybe you can play around with tic and achieve
whatever you're trying to achieve...

-Ade.
-- 
Internet  : mbarkah@slate.mines.colorado.edu    (NeXT Mailable)
CompuServe: 74160,3404

-----------------------------

From: Hans Mulder <hm@fwi.uva.nl>
Subject: Re: How do I increase number of screen rows?
Keywords: rows stty
Date: 19 Nov 92 00:47:12 GMT
To:       info-unix@sem.brl.mil

In <lux.721768908@sol.UVic.CA> lux@sol.UVic.CA (Michael O'Henly) writes:

>    I want to increase the number of rows displayed by things like
>emacs and nn from 24 to 35.

>    When I dial into my machine, the terminal window is defined as
>24x80 and I can't quite figure out how to change it. I suspect it
>involves the stty command, but 'stty rows 35' doesn't seem to tell
>"full screen" emacs whatever it needs to know in order to address the
>extra rows.

You need to say "stty rows 35 columns 80" (or whatever).

--
HansM

-----------------------------

From: Ade Barkah <mbarkah@slate.mines.colorado.edu>
Subject: Re: Internet question
Date: 19 Nov 92 01:02:30 GMT
To:       info-unix@sem.brl.mil

13501TMC@MSU (Tim Casey) writes:
: 
:      Does anyone know the cost associated with getting Internet access from
: home (i.e. a direct hookup compared to sharing time on a server)?

That greatly depends on what you want (i.e., the speed and type
of the connection.) Using serial modems, 'SLIP' is the most popular
method to connect to the net. Speeds range from 9600-38.4kbps,
and the cost is around $200 a month depending on your internet
provider. You'ld also need the appropriate software for this
(inet packages for unix, plus the SLIP, which is actually free.
DOS and OS/2 users probably need some sort of a TCP/IP package.
I'd say they're around $150-$250.) Add whatever it will cost
to have a dedicated phone line.

More dedicated lines are, of course, more expensive. Companies
like UUNET have 56.4kbps leased lines available... it may cost
around $1000 to set it up, and several hundred a month to run.
Then there are T1/T3 lines. I think those cost about $3000 to
set up and somewhere around $1000/month to run. For uunet, you
can ftp their rates and policy from 'ftp.uu.net.' I'm not
associated to uunet in any way, it's just that that's about
the only company I'm vaguely familiar with.

Regards,


-Ade.
-- 
Internet  : mbarkah@slate.mines.colorado.edu    (NeXT Mailable)
CompuServe: 74160,3404

-----------------------------

From: Aaron Duncan <aaron@coombs.anu.edu.au>
Subject: awk info
Date: 19 Nov 92 01:46:53 GMT
NNTP-Posting-Host: 150.203.76.2
To:       info-unix@sem.brl.mil

I was wondering if anyone could tell me of any awk tutorials
available on anonymous-ftp or any other useful source on the language.

Please mail me as I don't normally follow this group.

Thanks in advance,

Aaron Duncan
aaron@coombs.anu.edu.au

-----------------------------

From: Kenneth Ng <ken@sugra.uucp>
Subject: Re: Unattended execution
Date: 19 Nov 92 03:39:26 GMT
To:       info-unix@sem.brl.mil

In article <BxsH17.Cuu@magpie.nycenet.edu: manes@magpie.nycenet.edu (Steve Manes) writes:
:Bob Lee (rlee@bgsu.edu) wrote:
:: There is a task I want to perform, it includes recursively searching over
:: 200 directories and over 1000 files for an occurance of a text string in
:: any of the files. As you probably guessed, this task takes quite a while
:: and I want to do it for more than one text string.
:See at(C).

At on my machine will schedule a task to run at a certain time.  I had a real
dangerous script that looked for printable files, greped out a string, and
than ran sed to replace all occurrance of that string with a new string.
Real dangerous if some novice decides to change all 'a' to 'b' :-).  The
relevant part of the code is:

gfind . -type f -print | xargs printable | xargs grep "stuff" \
| awk -F: '{ print $1 }' | sort | uniq

Now, what this does in english :-).  gfind finds all files I want to deal
with, modify to your hearts content.  'printable' was a local function to
determine what files one wanted to look at (it ignored object code, data
bases, etc), the grep searches for the string I want, the awk yanks out
the file name, the 'sort | uniq' gives me a unique list of the files that
contain the string.  And for the curious, this is the program I piped the
output into to change all the strings (from memory):

#! /bin/csh
foreach file ($*)
   cp ${file} ${file}.save
   sed 's/old/new/g' < ${file}.save > ${file}
   end

Be warned, this routine can be VERY dangerous if you are not real careful
about what you want to change.


-- 
Kenneth Ng
Please reply to ken@eies2.njit.edu for now.
Apple and AT&T lawsuits: Just say NO!

-----------------------------

From: Thad P Floryan <thad@cup.portal.com>
Subject: Re: What's HP Boat Format
Date: 19 Nov 92 06:48:27 GMT
To:       info-unix@sem.brl.mil

In article <1992Nov16.180950.21931@leland.Stanford.EDU>
donghao@leland.Stanford.EDU (dong hao zhang) writes:

|  I have a 3.5 inch floppy disk to read. The disk is marked HP boat format.
|  Is this the disk format for HP workstations ? I appreciate any response to
|  donghao@leland.stanford.edu
|  
|  Sorry if this isn't quite a unix question, but couldn't find any place
|  better.

"HP boat format"?   Sounds like a question for the "rec.boating" newsgroup.

Naw, cannot make the same typo twice (article header and article body), so:

102' fibreglass hull, twin diesels.  And the 3-1/2" disks make nice hub
shims for my Penn Ocean reels, especially important when using 150 pound/test
line.  Just don't get caught dropping a line in at HP's Monterey Bay Aquarium.

HP also has two corporate airplanes mfd. by Lockheed; those would be the
"HP airplane format".

:-)  :-)  :-)

Seriously, though the disk may be marked "BOOT format", is that what's really
on the disk?  In other words, did someone simply re-use a boot disk to send
you stuff?

Thad Floryan [ thad@btr.com, thad@cup.portal.com ]

-----------------------------

From: Scott Sanbeg <ssanbeg@visual.spk.wa.us>
Subject: Re: Absurd! (Re: IS UNIX DEAD)
Date: 19 Nov 92 07:51:17 GMT
To:       info-unix@sem.brl.mil

In article <Bxvu0w.BwD@research.canon.oz.au> luke@research.canon.oz.au (Luke Kendall) writes:
>This `is Unix dead' is one of the most stupid subjects I have ever seen
>discussed.

Agreed. From my own perspective UNIX was designed with elegance built
in that has survived to this day - neophtes to the OS haven't changed
that opinion. Is would be easiest to manage if the thread, though, stay
under the '..UNIX DEAD' Subject line for a single kill file entry.
Scott

 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Scott Sanbeg     UNIX Systems Administrator       (509)535-2561
ssanbeg@visual.spk.wa.us (or) ...!uunet!tau-ceti!visual!ssanbeg

-----------------------------

From: Tero Laakkonen <laakkone@klaava.helsinki.fi>
Subject: Re: Absurd! (Re: IS UNIX DEAD)
Date: 19 Nov 92 09:27:04 GMT
To:       info-unix@sem.brl.mil

In <Bxvu0w.BwD@research.canon.oz.au> luke@research.canon.oz.au (Luke Kendall) writes:

>This `is Unix dead' is one of the most stupid subjects I have ever seen
>discussed.
>  1) Some people seem to be confusing operating systems with the
>     applications that run under the OS.

i agree with this. what also irritates me is people continuously
changing the subject line ...

-tero

-----------------------------

From: Michael Salmon <etxmesa@eos.ericsson.se>
Subject: Re: It ain't a 24x80 world anymore. Or is it?
Date: 19 Nov 92 09:09:38 GMT
To:       info-unix@sem.brl.mil

In article <lux.722129357@sol.UVic.CA>, 
lux@sol.UVic.CA (Michael O'Henly) writes:
|>     A few days ago I posted a query about how to increase the number
|> of rows displayed in a terminal window so that 'full-screen' commands
|> like emacs could make use 35 lines instead of the usual 24.
|> 
|>     I got some responses that suggested "stty rows 35" or "setenv
|> LINES 35". I've tried both and, while they do alter the terminal's
|> behaviour, they don't give me a 35-line screen. What I'm getting looks
|> like this: lines 1-24 after a screen-clear display correctly, but
|> lines 25-35 pile up on top of each other on the 24th line.
|> 
|>     So maybe I didn't ask the right question. What I'm trying to do is
|> make the best use of my laptop screen when I dial into my machine
|> using a modem and terminal emulator. Does the fact that I'm dialing in
|> make a difference? I'm sure there _must_ be a way of working with more
|> than a 24x80 display under these circumstances.

I use SunOS 4.1.1 and I mention that only because it reflects the
curses that I use. When I use an xterm window it sets the TERMCAP
environment variable to the value stored in the terminfo database but
with the #li and #co values set to the correct size. tcsh updates this
whenever it receives the window has changed size signal (SIGWINCH). I
think that the problem with setting LINES is that you are telling the
program how long the screen is but curses still believes that it is 24.
I suggest therefore that you set your TERMCAP variable to suit, the
resize program in the X11 release may be of some use, at least as a
starting point.

-- 

Michael Salmon

#include	<standard.disclaimer>
#include	<witty.saying>
#include	<fancy.pseudo.graphics>

Ericsson Telecom AB
Stockholm

-----------------------------

From: Roberto Shironoshita <shirono@ssd.csd.harris.com>
Subject: Re: It ain't a 24x80 world anymore. Or is it?
Date: 19 Nov 92 16:44:21 GMT
NNTP-Posting-Host: gcx1.ssd.csd.harris.com
To:       info-unix@sem.brl.mil

In article <lux.722129357@sol.UVic.CA> lux@sol.UVic.CA (Michael O'Henly) writes:

>     I got some responses that suggested "stty rows 35" or "setenv
> LINES 35". I've tried both and, while they do alter the terminal's
> behaviour, they don't give me a 35-line screen. What I'm getting looks
> like this: lines 1-24 after a screen-clear display correctly, but
> lines 25-35 pile up on top of each other on the 24th line.
>
>     So maybe I didn't ask the right question. What I'm trying to do is
> make the best use of my laptop screen when I dial into my machine
> using a modem and terminal emulator. Does the fact that I'm dialing in
> make a difference? I'm sure there _must_ be a way of working with more
> than a 24x80 display under these circumstances.

Does your terminal emulator support more than 24 lines?  From your
description of what happens when you instruct your applications that you
have a 35-line display, it sounds as if your terminal emulator is happily
piling the last 12 lines on top of one another.

I have had no problems using xterm in a non-standard size (e.g. 55x80) to
rlogin to other systems where I told vi that my line-count was 55.
--

     Roberto Shironoshita      ||   Internet: shirono@ssd.csd.harris.com
      Harris Corporation       ||
   Computer Systems Division   ||   UUCP: ...!uunet!ssd.csd.harris.com!shirono
                               ||
DISCLAIMER: The opinions expressed here are my own; they in no way reflect the
            opinion or policies of Harris Corporation.

-----------------------------

From: Elizabeth Haley <haley@husc11.harvard.edu>
Subject: Re: How does a mortal become a UNIX WIZARD ?
Date: 19 Nov 92 10:26:22 GMT
To:       info-unix@sem.brl.mil

mbarkah@slate.mines.colorado.edu (Ade Barkah) writes:


>What does it take for a man, er, person, to become a Unix Wizard ?

>Which bibles should we study ? (after memorizing O'Rileys to become
>  an X Wizzie ?)
K & R C, and anything release by ATT, then all the code released by
BSD.
You shoud know them by heart...
>How many kernels (and which ones) we need to take apart and reassemble ?
All of them.
>Some doth say that the only way thou shall gain salvation is to
>partake in the (sacrireligios) ceremony of rewriting Unix from
>scratch.
No, merely write a small working kernal by using
cat > kmem

>So, oh, mylord, how does a mortal become a Unix Wizard ?
Seriously, time, and much study.
Write programs, write device drivers, reconfigure your kernal 1000
thousand times, to make a little faster or a little more efficient...
Get a 386 box, and get 386BSD running on it, then go through the code
for it until you understand how it all adds up.
Then you will be a *novice* wizard :-)
Or read the FAQ in comp.unix.wizards, and follow that view...

>(next question: how does a newbie become a net.personality ?)
Have an answer for everything, either useful or useless...
>(ade barkah)
>-- 
>Internet  : mbarkah@slate.mines.colorado.edu    (NeXT Mailable)
>CompuServe: 74160,3404
-- 
=---------------------------------------------------------------------------=
=The author of this letter is a fabulously intelligent person and is very   =
=Silly. She is also remarkably well loved, by the author of this signature. =
=---------------------------haley@husc9.harvard.edu-------------------------=

-----------------------------

From: "John D. Boggs" <jboggs@umaxc.weeg.uiowa.edu>
Subject: Re: How does a mortal become a UNIX WIZARD ?
Date: 20 Nov 92 14:19:23 GMT
To:       info-unix@sem.brl.mil

From article <Mf30lBO00VI=41tGYT@andrew.cmu.edu>, by Geoffrey Spear <gs32+@andrew.cmu.edu>:
> 	Also, read the jargon file and start using obscure hacker jargon all
> the time.  It will at least make you *seem* to be a wizard of some sort,
> at least to those who have no idea what you're talking about and who are
> afraid to admit it :)

Plus there's the fact that some poet (Auden?) said that we all pretend to
be something before we really are it, so yeah, pretending to be a Unix 
wizard is a step in the right direction.

> "You're redlining my bogometer!"
                       ~~~~~~~~~
Hey!  You making fun of my name??!

-John D. Boggs     uunet!erato!jdb

-----------------------------

From: Peter Busser <peter@global.hacktic.nl>
Subject: Re: IS UNIX DEAD? (long)
Date: 20 Nov 92 00:38:31 GMT
To:       info-unix@sem.brl.mil

lytras@avalon.physik.unizh.ch (Apostolos Lytras) writes:

>Well, let's see:

>(let's take book editing software for an example)

>FrameMaker:  about $3000 (if I convert the swiss price to US$, might be
>                          less in the US, however)

>You get almost the same under UNIX from
>Emacs & TeX:       $0 (maybe you'll have to add media cost)

That's rediculous! emTeX for DOS or OS/2 costs as much and offers as much. But
it isn't Framemaker. So what you say here has nothing to do with what were
talking about: the difference in numbers and prices of applications.

>Or take some table editing programs (spreadsheets), that offer macros:
>Excel:  well.... $500?
>Perl:              $0

Sorry, but these are rediculous comparissons. You can't compare a bicycle with
an train. Just like you can't compare X11 with COMMAND.COM. I mean, Perl and
Excel are two completely different kind of programs. I can program a
spreadsheet in C, but that doesn't make C a spreadsheet... Or does it?

>Maybe you start to understand now why I just *love* UNIX... it just
>compares favorably with DOS, and I don't give a **** about
>"user-friendly" interfaces which seem to be in the way all the time (to
>the experienced user, at least). 

I agree, but we were not discussing what you or I like. For me personally, I
couldn't care less if UNIX is going to change or not. But, it might be better
for UNIX to have a larger market. It might get squashed between other products
if it doesn't grow.

>Did you ever look at what the cost is for adding your DOS/Windows-PC to
>a network?

I know, don't tell me things I knew for years. I'm not a DOS user, I don't
like the dumb PC networks like Novell and others. You don't need to convince
me about the good things of UNIX (and not of the bad things :). The point is,
you can't say: "Hey, look at this nice hacker friendly whiz-bang UNIX system
with a feeping creaturizm shell, a nice VI editor and gcc, make, Perl, awk,
TCP/IP, NFS, X, and all the other goodies installed!". I like it, you like it,
but it scares other people.

The argument about connecting PCs to a network: well who cares? A UNIX machine
has an administrator (according to some posters here), well so has a PC
network. Period.

"But the system wasn't ment for end-users". It's an invalid argument, the
system as in operating system, was ment for interactive use. The *user
interface*, was ment for hackers. There is no reason why we can't have a
second user interface that was ment for end-users. Preferably a consistent
GUI. Even MS-DOS offers a shell and I think it even installs by default. So
why can't most UNIXes have such a thing?

-----------------------------

From: Apostolos Lytras <lytras@avalon.physik.unizh.ch>
Subject: Re: IS UNIX DEAD? (long)
Date: 20 Nov 92 15:04:13 GMT
To:       info-unix@sem.brl.mil


In article <1992Nov20.003831.969@global.hacktic.nl> you write:
>That's rediculous! emTeX for DOS or OS/2 costs as much and offers as much. But
>it isn't Framemaker. So what you say here has nothing to do with what were
>talking about: the difference in numbers and prices of applications.

Indeed, it's not framemaker, and it doesn't offer the same things
either, but it's far superior to framemaker. That's why the comparison
may be ridiculous, but that's just because prices for useless apps like
framemaker are THAT high. Maybe you're right, the comparison was just
TOO flattering for FrameMaker. But I wanted to compare with something
that is available on the same amount of hardware on both sides, which is
- as you say - a ridiculous thing to try, because DOS is dead, and UNIX
isn't.

[Perl and Excel]
>Sorry, but these are rediculous comparissons. You can't compare a bicycle with
>an train. Just like you can't compare X11 with COMMAND.COM. I mean, Perl and
>Excel are two completely different kind of programs. I can program a
>spreadsheet in C, but that doesn't make C a spreadsheet... Or does it?

You can program a spreadsheet in Excel, too, and it doesn't make Excel a
spreadsheet either (I won't indulge in my views on spreadsheets, because
then I'd have to justify my belief that spreadsheets are the most
useless applications ever invented, worse than computer games). The
comparison just works, because Excel isn't a spreadsheet, you have to
program it in a cryptic macro language to get real use from it, and it
will be slower than perl, once you finished. Same applies to perl, but
it's faster and cheaper. I had to evaluate a few megabytes of numeric
data this fall and did it in both, so I know what I'm talking about,
perl just did the job a) EASIER!, b) faster, c) cheaper than Excel.
We're talking business here, and time is money, I just can't afford to
pay $500 and get less performance than from free software.

>I know, don't tell me things I knew for years. I'm not a DOS user, I don't
>like the dumb PC networks like Novell and others. You don't need to convince
>me about the good things of UNIX (and not of the bad things :). The point is,
>you can't say: "Hey, look at this nice hacker friendly whiz-bang UNIX system
>with a feeping creaturizm shell, a nice VI editor and gcc, make, Perl, awk,
>TCP/IP, NFS, X, and all the other goodies installed!". I like it, you like it,
>but it scares other people.

And you get impressed by the masses. There is a saying in switzerland
that goes: "Eat cow shit, millions of flies can't be wrong". It might
scare somebody, but we are experiencing an enormous growth in computer
knowledge among our population, so we're just not anymore at a point
where computers absolutely HAVE to have an interface with annoying
dialog boxes flashing up every other second. These people want
performance, they want to get their jobs done, and they have the
knowledge to handle a computer that is hacker friendly. These people are
UNIX people, and the market will grow, because they are on the rise. Why
stop them with awkward user interfaces, that have been licensed and
implemented by bozos? 

>The argument about connecting PCs to a network: well who cares? A UNIX machine
>has an administrator (according to some posters here), well so has a PC
>network. Period.

*laugh* You must be joking. WHICH PC network, if you please? I don't see
many PC's networking, when you look at the market as a whole, and why is
that so?

>"But the system wasn't ment for end-users". It's an invalid argument, the
>system as in operating system, was ment for interactive use. The *user
>interface*, was ment for hackers. There is no reason why we can't have a
>second user interface that was ment for end-users. Preferably a consistent
>GUI. Even MS-DOS offers a shell and I think it even installs by default. So
>why can't most UNIXes have such a thing?

That wasn't my argument, but let me answer to this quickly.
NeXTstep has it, OpenWindows has it, OSF/1 has it... even Linux has
one. In fact, only DOS users don't have one consistent GUI (windows is a
joke, windows NT will be a bad joke, os/2 adds to this variety, a.s.o).

Cheers
- A.

-- 
	 lytras@ifi.unizh.ch   		|   Apostolos Lytras
	 lytras@avalon.physik.unizh.ch	|   Informatik Club der Uni
	 lytras@amiga.physik.unizh.ch  	|   Zuerich, SysAdmin

-----------------------------

From: Rob McMahon <cudcv@csv.warwick.ac.uk>
Subject: Re: IS UNIX DEAD? (long)
Date: 20 Nov 92 16:28:20 GMT
NNTP-Posting-Host: sprocket.csv.warwick.ac.uk
To:       info-unix@sem.brl.mil

In article <1992Nov20.003831.969@global.hacktic.nl> peter@global.hacktic.nl
(Peter Busser) writes: 
>>FrameMaker:  about $3000 (if I convert the swiss price to US$, might be
>>                          less in the US, however)
>
>>You get almost the same under UNIX from
>>Emacs & TeX:       $0 (maybe you'll have to add media cost)
>
>That's rediculous! emTeX for DOS or OS/2 costs as much and offers as much. But
>it isn't Framemaker. So what you say here has nothing to do with what were
>talking about: the difference in numbers and prices of applications.

Comparing emacs & TeX with FrameMaker is indeed ridiculous (although I confess
I prefer working that way), but FrameMaker cost us <\pounds 200 one-off,
including printed documentation, ~\pounds 100 each for more than 5 floating
licences, running on Sun workstations.  Interleaf came in at something like
\pounds 30-40 a licence, but FrameMaker seemed to be worth the extra money.
That't not so ridiculous.

Rob
-- 
UUCP:   ...!mcsun!uknet!warwick!cudcv	PHONE:  +44 203 523037
JANET:  cudcv@uk.ac.warwick             INET:   cudcv@warwick.ac.uk
Rob McMahon, Computing Services, Warwick University, Coventry CV4 7AL, England

-----------------------------

From: Peter Busser <peter@global.hacktic.nl>
Subject: Re: IS UNIX DEAD? (very long)
Date: 20 Nov 92 00:45:06 GMT
To:       info-unix@sem.brl.mil

papresco@undergrad.math.waterloo.edu (Paul Prescod) writes:

>Non standard QWERTY-incompliant keyboards are certainly not my problem.
>99.9% of qwerty keyboards (and every one I have seen) has a semicolon beside
>the l.  The other .1% are so nonstandard that perhaps their hjkl aren't
>in a row either.

_American_ keyboards you mean...

>Thus the beauty of the (till now) unused F1 key.  Besides, one would
>assume that VI would be configurable enough that you could change the
>key mappings of the keys!  Or at least turn off help if you wanted to.

:map

-----------------------------

From: Craig Marby <marby@laura.harvard.edu>
Subject: Re: Recursive Tree Copy (with filter)?
Date: 20 Nov 92 02:16:54 GMT
To:       info-unix@sem.brl.mil

>>>>> On 19 Nov 92 21:17:48 GMT, trw@unixland.natick.ma.us (Tim Weil) said:

Tim> I need a utility that would perform a recursive tree copy but only 
Tim> operates on a selected file set for transfers.  The specific problem
Tim> concerns a complicated source tree with Makefiles embedded at various
Tim> sub-directories throughout the tree.
Tim>  
Tim> What the utility might do is behave like "cp -r" and "grep make *"
Tim> where any file prepended with "make" would be copied along with the
Tim> attached subdirectory.
Tim>  

What you need to do is a find/cpio -p. In other words generate your
filter or whatever using find -- if that doesn't quite give you
what you want you can redirect the find to an output file and
then edit that. Once you have your list of files you then send this
on to cpio -p, that is cpio with the "-p" option. See the manual
for details. You may wish to do a mini-experiment first!

Hope this helps.

    __o         
  _ \<,_       Craig A. Marby    marby@layla.harvard.edu
 (_)/ (_)      
~~~~~~~~~~
--

    __o         
  _ \<,_       Craig A. Marby    marby@layla.harvard.edu
 (_)/ (_)      
~~~~~~~~~~

-----------------------------

From: Mike Miller <millerm@skie.ece.orst.edu>
Subject: LaTeX Compilation
Keywords: LaTeX TeX Apollo DomainOS
Date: 20 Nov 92 02:36:28 GMT
NNTP-Posting-Host: skie.ece.orst.edu
To:       info-unix@sem.brl.mil

Has anyone had any success in compiling the LaTeX code on HP/Apollo  
DomainOS 10.3? We are having a great deal of difficulities in compiling  
the code due to diffrences and quirks in the DomainOS.

If you have any knowledge of how to, or how not to, or have the modified  
code (or bin) files we would greatly appreicate it if you could contact us  
via email as we often do not get the chance to read all of the news on a  
regular basis.

Thank you for you time and consideration.

ECE Support, Oregon State University
millerm@skie.ece.orst.edu    ---NeXT mail accepted---

-----------------------------

From: Ted M A Timar <tmatimar@empress.com>
Subject: Welcome to comp.unix.questions [Biweekly posting]
Date: 20 Nov 92 06:00:32 GMT
Expires: 18 Dec 1992 06:00:22 GMT
Followup-To: comp.unix.questions
Supersedes: <unix-faq/unix-intro_721029617@athena.mit.edu>
NNTP-Posting-Host: pit-manager.mit.edu
X-Last-Updated: 1992/10/21
To:       info-unix@sem.brl.mil

Archive-name: unix-faq/unix-intro
Version: $Id: unix-intro,v 2.0 92/10/20 12:08:28 tmatimar Exp $

Comp.unix.questions is one of the most popular and highest volume
newsgroups on Usenet.  This article is a monthly attempt to remind
potential posters about what is appropriate for this newsgroup.
If you would like to make any suggestions about the content of
this article, please contact its maintainer at
tmatimar@empress.com.

Companion articles include the answers to some Frequently
Asked Questions.  You may save yourself a lot of time by reading
those articles before posting a question to the net.

If you have not already read the overall Usenet introductory material
posted to "news.announce.newusers", please do.  Much of this article
overlaps with the common sense guidelines posted there.

	     Should I Post My Unix Question to the Net?

Often the answer is "No, you can get an answer a lot faster without
posting a question." Before you post, you should try -

    o Reading the manual for your system.  Some day you may encounter
      the phrase "RTFM", which stands for "Read the Fine Manual"
      (except 'F' doesn't really stand for "Fine").  If you ask
      someone a question and they tell you to RTFM, it's an
      indication that you haven't done your homework.   For instance,
      if you are having trouble removing a file whose name begins
      with a "-", check the man page for "rm".  It might tell
      you what you need to know.

      When people use terminology like "read(2)", they are referring
      to the "read" man page in section 2 of the manual (which you
      would see by using "man 2 read").

    o Finding a knowledgeable user at your site.  Many sites have
      at least a few Unix experts who will be happy to help you
      figure out how to remove a file whose name begins with "-".
      Many larger sites, particularly universities, may even have
      paid consultants whose job is to help you with Unix problems.
      Check with them first.

    o Find a good introductory book on Unix.  There are plenty of
      such books available, and you will save yourself a lot
      of trouble by having one handy and consulting it frequently.
      (Question 1.5 in the companion articles will let you know
       where you can find a list of good Unix and C books.)

Please remember that the comp.unix.* newsgroups are read by over 80,000
people around the world, and that posting a question to this group will
cost a lot of time and money by the time your article is distributed to
Asia, Australia, Europe (west and east), Africa, the middle east,
and all corners of North, South and Central America.

Also, some people receive these newsgroups as part of a mailing list
rather than a newsgroup.  If you're one of these people, please don't
send a "Remove me from this list" or "UNSUBSCRIBE"  message to the
wrong place.  Take the time to figure out where you're getting this
stuff from, and send your request to the mailing list maintainer, *not*
to the list or newsgroup itself!  Ask your local postmaster for help.
(One of the answers in the companion articles deals with the details of
the mailing list.)

               To Which Newsgroup Should I Post My Question?

The choice of newsgroup is harder than it used to be.  In the old days,
you just had to choose between "comp.unix.questions" and
"comp.unix.wizards".  Now there are a variety of more specific groups.
Choose one of the following groups carefully.  If you aren't sure where
your question belongs or if your question is not specific to some
particular version of Unix, try "comp.unix.questions".  Many
knowledgeable Unix wizards read that group and will be able to help you.

Here are the capsule descriptions of various groups you might consider
(extracted from a monthly posting to "news.announce.newusers")

comp.unix.questions     General questions from UNIX users and sys admins.
			If your question isn't a really good match for one of
			the groups below, post it here.

news.answers		Repository for periodic USENET articles. (Moderated)
			This article is crossposted there.
			Do not try to post here unless you're
			posting a list of FAQ's and their answers.

comp.unix.shell         Using and programming any UNIX shell.

comp.lang.c             Discussion about C.

comp.sources.unix       Postings of complete, UNIX-oriented sources. (Moderated)
comp.std.unix           Discussion for the P1003 committee on UNIX. (Moderated)
comp.unix               Discussion of UNIX* features and bugs. (Moderated)
comp.unix.admin         Administering a Unix-based system.
comp.unix.aix           IBM's version of UNIX.
comp.unix.amiga		Unix on the Commodore Amiga
comp.unix.aux           The version of UNIX for Apple Macintosh II computers.
comp.unix.bsd           Discussions relating to BSD UNIX.
comp.unix.internals     Discussions on hacking UNIX internals.
comp.unix.large         UNIX on mainframes and in large networks.
comp.unix.misc          Various topics that don't fit other groups.
comp.unix.msdos         MS-DOS running under UNIX by whatever means.
comp.unix.programmer    Q&A for people programming under Unix.
comp.unix.sysv286       UNIX System V (not XENIX) on the '286.
comp.unix.sysv386       Versions of Unix (not Xenix) on Intel 80386-based boxes.
comp.unix.ultrix        Discussions about DEC's Ultrix.
comp.unix.xenix.misc    General discussions regarding XENIX (except SCO).
comp.unix.xenix.sco     XENIX versions from the Santa Cruz Operation.

comp.unix.wizards       In-depth discussions of advanced unix topics.
			People should not post to this group unless they
			have used unix as a user, sysadmin and know details
			of the kernel, and how different unix kernels differ.
			In other words, don't post to comp.unix.wizards.

	      What Information Should I Include?

It's hard to include too much information.  There are hundreds of
different Unix systems out there, and they all have less in common
than you might think.  If you have a problem and are posting an
article, please be sure to mention:

    o A descriptive subject line.  Many people will decide whether
      to read your article solely on the basis of the subject line,
      so it should be a good statement of your problem.

      NOT GOOD                          GOOD

      "Help"                            "How do I sort a file by line length?"
      "Csh question"			"csh dumps core when I use '$<'"

    o What computer you are using, and what specific version
      of the operating system it uses.  For instance,

	    SunOS 4.0.1, Sun 3/50
	    4.3BSD-tahoe, Vax 11/780
	    SVR3.2, 3b2

    o If possible, the *exact* text of any error message you
      may have encountered.

      WRONG				RIGHT

      "I can't print this file"     "When I type 'lpr Filename', I get
				      lpr: Filename: File too ugly to print
				     What does this mean?  It isn't in
				     the man page.  This is using
				     Mueslix 9.3 on a Fax 68086502"

It's a good idea to post unrelated questions in separate articles,
so that people can keep different discussions separate.   It's also
a *very* good idea to include a line or two like this:

    "Please mail your answers to me and I'll summarize what I get
     and post the results to comp.unix.questions."

This prevents many identical responses from different users to the
same question from clogging up the newsgroup.  And make sure
you really summarize what you get - don't just concatenate
all the mail you've received.

It's also a good idea to read comp.unix.questions for at least a couple
of weeks after you post your article to see what followup articles
are posted.

                Should I Post an Answer to a Question?

It's very tempting to post an answer to a question you read on the net,
especially when you think "Aha, finally - a question I can answer!"
Consider though that when a simple question is asked, such as the
sort about to be answered below, many other people around the
world already know the answer and may be posting their own reply.
In order to avoid dozens of replies to simple questions, please
wait a day or so and see if anyone else has already answered
the question.  If you have something special to contribute, please
do so, but make sure you're not duplicating something someone else has
already done.

You should feel free to reply to any question >by email<.  Even if
the user gets 200 responses to his question, at least the load on the
rest of the net is minimized.

                    What About Posting Source Code?

Posting small amounts of example code is fine (use comp.sources.unix to
distribute complete programs) - but please make sure that your code
runs (or at least compiles) properly.  Don't just type it in while
editing your posting and hope it will work, no matter how sure you are
that it will.  We all make mistakes.

                        What About Those People
       Who Continue to Ask Stupid or Frequently Asked Questions
         In Spite of The Frequently Asked Questions Document?

Just send them a polite mail message, possibly referring them to this document.
There is no need to flame them on the net - it's busy enough as it is.
-- 
Ted Timar - tmatimar@empress.com
Empress Software, 3100 Steeles Ave E, Markham, Ont., Canada L3R 8T3

-----------------------------

From: Ted M A Timar <tmatimar@empress.com>
Subject: Frequently Asked Questions about Unix (index) [Biweekly posting]
Date: 20 Nov 92 06:00:44 GMT
Expires: 18 Dec 1992 06:00:22 GMT
Followup-To: comp.unix.questions
Supersedes: <unix-faq/contents_721029617@athena.mit.edu>
NNTP-Posting-Host: pit-manager.mit.edu
X-Last-Updated: 1992/10/21
To:       info-unix@sem.brl.mil

Archive-name: unix-faq/contents
Version: $Id: contents,v 2.0 92/10/20 12:06:12 tmatimar Exp $

The following seven articles contain the answers to some Frequently Asked
Questions often seen in comp.unix.questions and comp.unix.shell.
Please don't ask these questions again, they've been answered plenty
of times already - and please don't flame someone just because they may
not have read this particular posting.  Thank you.

These articles are divided approximately as follows:

      1.*) General questions.
      2.*) Relatively basic questions, likely to be asked by beginners.
      3.*) Intermediate questions.
      4.*) Advanced questions, likely to be asked by people who thought
	   they already knew all of the answers.
      5.*) Questions pertaining to the various shells, and the differences.
      6.*) An overview of Unix variants.

The following questions are answered:

      1.1)  Who helped you put this list together?
      1.2)  When someone refers to 'rn(1)' or 'ctime(3)', what does
              the number in parentheses mean?
      1.3)  What does {some strange unix command name} stand for?
      1.4)  How does the gateway between "comp.unix.questions" and the
              "info-unix" mailing list work?
      1.5)  What are some useful Unix or C books?
      1.6)  What happened to the pronunciation list that used to be
              part of this document?

      2.1)  How do I remove a file whose name begins with a "-" ?
      2.2)  How do I remove a file with funny characters in the filename ?
      2.3)  How do I get a recursive directory listing?
      2.4)  How do I get the current directory into my prompt?
      2.5)  How do I read characters from the terminal in a shell script?
      2.6)  How do I rename "*.foo" to "*.bar", or change file names
              to lowercase?
      2.7)  Why do I get [some strange error message] when I
              "rsh host command" ?
      2.8)  How do I {set an environment variable, change directory} inside a
              program or shell script and have that change affect my
              current shell?
      2.9)  How do I redirect stdout and stderr separately in csh?
      2.10) How do I tell inside .cshrc if I'm a login shell?
      2.11) How do I construct a shell glob-pattern that matches all files
            except "." and ".." ?
      2.12) How do I find the last argument in a Bourne shell script?
      2.13) What's wrong with having '.' in your $PATH ?

      3.1)  How do I find out the creation time of a file?
      3.2)  How do I use "rsh" without having the rsh hang around
              until the remote command has completed?
      3.3)  How do I truncate a file?
      3.4)  Why doesn't find's "{}" symbol do what I want?
      3.5)  How do I set the permissions on a symbolic link?
      3.6)  How do I "undelete" a file?
      3.7)  How can a process detect if it's running in the background?
      3.8)  Why doesn't redirecting a loop work as intended?  (Bourne shell)
      3.9)  How do I run 'passwd', 'ftp', 'telnet', 'tip' and other interactive
              programs from a shell script or in the background?
      3.10) How do I find out the process ID of a program with a particular
            name from inside a shell script or C program?
      3.11) How do I check the exit status of a remote command
            executed via "rsh" ?
      3.12) Is it possible to pass shell variable settings into an awk program?
      3.13) How do I get rid of zombie processes that persevere?
      3.14) How do I get lines from a pipe as they are written instead of
            only in larger blocks.

      4.1)  How do I read characters from a terminal without requiring the user
              to hit RETURN?
      4.2)  How do I check to see if there are characters to be read without
              actually reading?
      4.3)  How do I find the name of an open file?
      4.4)  How can an executing program determine its own pathname?
      4.5)  How do I use popen() to open a process for reading AND writing?
      4.6)  How do I sleep() in a C program for less than one second?
      4.7)  How can I get setuid shell scripts to work?
      4.8)  How can I find out which user or process has a file open or is using
            a particular file system (so that I can unmount it?)
      4.9)  How do I keep track of people who are fingering me?
      4.10) Is it possible to reconnect a process to a terminal after it has
            been disconnected, e.g. after starting a program in the background
            and logging out?
      4.11) Is it possible to "spy" on a terminal, displaying the output
            that's appearing on it on another terminal?

      5.1)  Can shells be classified into categories?
      5.2)  How do I "include" one shell script from within another
            shell script?
      5.3)  Do all shells have aliases?  Is there something else that
            can be used?
      5.4)  How are shell variables assigned?
      5.5)  How can I tell if I am running an interactive shell?
      5.6)  What "dot" files do the various shells use?
      5.7)  I would like to know more about the differences between the
            various shells.  Is this information available some place?

      6.1)  Disclaimer and introduction.
      6.2)  A very brief look at Unix history.
      6.3)  Main Unix flavors.
      6.4)  Unix Standards.
      6.5)  Identifying your Unix flavor.
      6.6)  Brief notes on some well-known (commercial/PD) Unices.
      6.7)  Real-time Unices.
      6.8)  Unix glossary.
      6.9)  Acknowledgements.

      7.1)  RCS vs SCCS:  Introduction
      7.2)  RCS vs SCCS:  How do the interfaces compare?
      7.3)  RCS vs SCCS:  What's in a Revision File?
      7.4)  RCS vs SCCS:  What are the keywords?
      7.5)  What's an RCS symbolic name?
      7.6)  RCS vs SCCS:  How do they compare for performance?
      7.7)  RCS vs SCCS:  Version Identification.
      7.8)  RCS vs SCCS:  How do they handle with problems?
      7.9)  RCS vs SCCS:  Conversion.
      7.10) RCS vs SCCS:  Support
      7.11) RCS vs SCCS:  Command Comparison
      7.12) RCS vs SCCS:  Acknowledgements
      7.13) Can I get more information on configuration management systems?

      If you're looking for the answer to, say, question 2.5, look in
      part 2 and search for the regular expression "^2.5)".

While these are all legitimate questions, they seem to crop up in
comp.unix.questions or comp.unix.shell on an annual basis, usually
followed by plenty of replies (only some of which are correct) and then
a period of griping about how the same questions keep coming up.  You
may also like to read the monthly article "Answers to Frequently Asked
Questions" in the newsgroup "news.announce.newusers", which will tell
you what "UNIX" stands for.

With the variety of Unix systems in the world, it's hard to guarantee
that these answers will work everywhere.  Read your local manual pages
before trying anything suggested here.  If you have suggestions or
corrections for any of these answers, please send them to to
tmatimar@empress.com.

-- 
Ted Timar - tmatimar@empress.com
Empress Software, 3100 Steeles Ave E, Markham, Ont., Canada L3R 8T3

-----------------------------

From: Ted M A Timar <tmatimar@empress.com>
Subject: Frequently Asked Questions about Unix (1/7) [Biweekly posting]
Date: 20 Nov 92 06:00:45 GMT
Expires: 18 Dec 1992 06:00:22 GMT
Followup-To: comp.unix.questions
Supersedes: <unix-faq/part1_721029617@athena.mit.edu>
NNTP-Posting-Host: pit-manager.mit.edu
X-Last-Updated: 1992/10/21
To:       info-unix@sem.brl.mil

Archive-name: unix-faq/part1
Version: $Id: part1,v 2.0 92/10/20 12:06:59 tmatimar Exp $

These seven articles contain the answers to some Frequently Asked
Questions often seen in comp.unix.questions and comp.unix.shell.
Please don't ask these questions again, they've been answered plenty
of times already - and please don't flame someone just because they may
not have read this particular posting.  Thank you.

These articles are divided approximately as follows:

      1.*) General questions.
      2.*) Relatively basic questions, likely to be asked by beginners.
      3.*) Intermediate questions.
      4.*) Advanced questions, likely to be asked by people who thought
	   they already knew all of the answers.
      5.*) Questions pertaining to the various shells, and the differences.
      6.*) An overview of Unix variants.
      7.*) An comparison of configuration management systems (RCS, SCCS).

This article includes answers to:

      1.1)  Who helped you put this list together?
      1.2)  When someone refers to 'rn(1)' or 'ctime(3)', what does
              the number in parentheses mean?
      1.3)  What does {some strange unix command name} stand for?
      1.4)  How does the gateway between "comp.unix.questions" and the
              "info-unix" mailing list work?
      1.5)  What are some useful Unix or C books?
      1.6)  What happened to the pronunciation list that used to be
              part of this document?

If you're looking for the answer to, say, question 1.5, and want to skip
everything else, you can search ahead for the regular expression "^1.5)".

While these are all legitimate questions, they seem to crop up in
comp.unix.questions or comp.unix.shell on an annual basis, usually
followed by plenty of replies (only some of which are correct) and then
a period of griping about how the same questions keep coming up.  You
may also like to read the monthly article "Answers to Frequently Asked
Questions" in the newsgroup "news.announce.newusers", which will tell
you what "UNIX" stands for.

With the variety of Unix systems in the world, it's hard to guarantee
that these answers will work everywhere.  Read your local manual pages
before trying anything suggested here.  If you have suggestions or
corrections for any of these answers, please send them to to
tmatimar@empress.com.

1.1)  Who helped you put this list together?

      I took over the maintenance of this list.  Almost all of the work
      (and the credit) for generating this compilation was done by
      Steve Hayman.

      We also owe a great deal of thanks to dozens of Usenet readers who
      submitted questions, answers, corrections and suggestions for this
      list.  Special thanks go to Maarten Litmaath, Guy Harris and
      Jonathan Kamens, who have all made many especially valuable
      contributions.

      Part 5 of this document (shells) was written almost entirely by
      Matthew Wicks <wicks@dcdmjw.fnal.gov>.

      Part 6 of this document (Unix flavours) was written almost entirely by
      Pierre (P.) Lewis <lew@bnr.ca>.

      Where possible the author of each question and the date it was last
      updated is given at the top.  Unfortunately, I only started this
      practice recently, and much of the information is lost.  I was also
      negligent in keeping track of who provided updates to questions.
      Sorry to those who have made valuable contributions, but did not
      receive the credit and recognition that they legitimately deserve.

1.2)  When someone refers to 'rn(1)' or 'ctime(3)', what does
      the number in parentheses mean?

      It looks like some sort of function call, but it isn't.  These
      numbers refer to the section of the "Unix manual" where the
      appropriate documentation can be found.  You could type "man 3
      ctime" to look up the manual page for "ctime" in section 3 of
      the manual.

      The traditional manual sections are:

	1	User-level  commands
	2	System calls
	3	Library functions
	4	Devices and device drivers
	5	File formats
	6	Games
	7	Various miscellaneous stuff - macro packages etc.
	8	System maintenance and operation commands

      Some Unix versions use non-numeric section names.  For instance,
      Xenix uses "C" for commands and "S" for functions.

      Each section has an introduction, which you can read with "man #
      intro" where # is the section number.

      Sometimes the number is necessary to differentiate between a
      command and a library routine or system call of the same name.
      For instance, your system may have "time(1)", a manual page about
      the 'time' command for timing programs, and also "time(3)", a
      manual page about the 'time' subroutine for determining the
      current time.  You can use "man 1 time" or "man 3 time" to
      specify which "time" man page you're interested in.

      You'll often find other sections for local programs or even
      subsections of the sections above - Ultrix has sections 3m, 3n,
      3x and 3yp among others.

1.3)  What does {some strange unix command name} stand for?

      awk = "Aho Weinberger and Kernighan"

	This language was named by its authors, Al Aho, Peter
	Weinberger and Brian Kernighan.

      grep = "Global Regular Expression Print"

	grep comes from the ed command to print all lines matching a
	certain pattern

		    g/re/p

	where "re" is a "regular expression".

      fgrep = "Fixed GREP".

	fgrep searches for fixed strings only.  The "f" does not stand
	for "fast" - in fact, "fgrep foobar *.c" is usually slower than
	"egrep foobar *.c"  (Yes, this is kind of surprising. Try it.)

	Fgrep still has its uses though, and may be useful when searching
	a file for a larger number of strings than egrep can handle.

      egrep = "Extended GREP"

	egrep uses fancier regular expressions than grep.  Many people
	use egrep all the time, since it has some more sophisticated
	internal algorithms than grep or fgrep, and is usually the
	fastest of the three programs.

      cat = "CATenate"

	catenate is an obscure word meaning "to connect in a series",
	which is what the "cat" command does to one or more files.  Not
	to be confused with C/A/T, the Computer Aided Typesetter.

      gecos = "General Electric Comprehensive Operating System"
	
	When GE's large systems division was sold to Honeywell,
	Honeywell dropped the "E" from "GECOS".

	Unix's password file has a "pw_gecos" field.  The name is a
	real holdover from the early days.  Dennis Ritchie has reported:

	    "Sometimes we sent printer output or batch jobs
	     to the GCOS machine.  The gcos field in the password file
	     was a place to stash the information for the $IDENT card.
	     Not elegant."

      nroff = "New ROFF"
      troff = "Typesetter new ROFF"
	
	These are descendants of "roff", which was a re-implementation
	of the Multics "runoff" program (a program that you'd use to
	"run off" a good copy of a document).

      tee       = T

	From plumbing terminology for a T-shaped pipe splitter.

      bss = "Block Started by Symbol"
	
	Dennis Ritchie says:

	    Actually the acronym (in the sense we took it up; it may
	    have other credible etymologies) is "Block Started by
	    Symbol." It was a pseudo-op in FAP (Fortran Assembly [-er?]
	    Program), an assembler for the IBM 704-709-7090-7094
	    machines.  It defined its label and set aside space for a
	    given number of words.  There was another pseudo-op, BES,
	    "Block Ended by Symbol" that did the same except that the
	    label was defined by the last assigned word + 1.  (On these
	    machines Fortran arrays were stored backwards in storage
	    and were 1-origin.)

	    The usage is reasonably appropriate, because just as with
	    standard Unix loaders, the space assigned didn't have to be
	    punched literally into the object deck but was represented
	    by a count somewhere.

      biff = "BIFF"

	This command, which turns on asynchronous mail notification,
	was actually named after a dog at Berkeley.

	    I can confirm the origin of biff, if you're interested.
	    Biff was Heidi Stettner's dog, back when Heidi (and I, and
	    Bill Joy) were all grad students at U.C. Berkeley and the
	    early versions of BSD were being developed.   Biff was
	    popular among the residents of Evans Hall, and was known
	    for barking at the mailman, hence the name of the command.

	Confirmation courtesy of Eric Cooper, Carnegie Mellon University

      rc (as in ".cshrc" or "/etc/rc") = "RunCom"

	"rc" derives from "runcom", from the MIT CTSS system, ca. 1965.

	    'There was a facility that would execute a bunch of
	    commands stored in a file; it was called "runcom" for "run
	    commands", and the file began to be called "a runcom."

	    "rc" in Unix is a fossil from that usage.'
	
	Brian Kernighan & Dennis Ritchie, as told to Vicki Brown

	"rc" is also the name of the shell from the new Plan 9
	operating system.

      Perl = "Practical Extraction and Report Language"

	The Perl language is Larry Wall's highly popular
	freely-available completely portable text, process, and file
	manipulation tool that bridges the gap between shell and C
	programming (or between doing it on the command line and
	pulling your hair out).  For further information, see the
	Usenet newsgroup comp.lang.perl.

      Don Libes' book "Life with Unix" contains lots more of these
      tidbits.

1.4)  How does the gateway between "comp.unix.questions" and the
      "info-unix" mailing list work?

      "info-unix" and "unix-qizards" are mailing list versions of
      comp.unix.questions and comp.unix.wizards respectively.
      There should be no difference in content between the
      mailing list and the newsgroup.

      To get on or off either of these lists, send mail to
      info-unix-request@brl.mil or unix-wizards-request@brl.mil.
      Be sure to use the '-Request'.  Don't expect an immediate response.

      Here are the gory details, courtesy of the list's maintainer,
      Bob Reschly.

      ==== postings to info-UNIX and UNIX-wizards lists ====

      Anything submitted to the list is posted; I do not moderate
      incoming traffic -- BRL functions as a reflector.  Postings
      submitted by Internet subscribers should be addressed to the list
      address (info-UNIX or UNIX- wizards);  the '-request' addresses
      are for correspondence with the list maintainer [me].  Postings
      submitted by USENET readers should be addressed to the
      appropriate news group (comp.unix.questions or
      comp.unix.wizards).

      For Internet subscribers, received traffic will be of two types;
      individual messages, and digests.  Traffic which comes to BRL
      from the Internet and BITNET (via the BITNET-Internet gateway) is
      immediately resent to all addressees on the mailing list.
      Traffic originating on USENET is gathered up into digests which
      are sent to all list members daily.

      BITNET traffic is much like Internet traffic.  The main
      difference is that I maintain only one address for traffic
      destined to all BITNET subscribers. That address points to a list
      exploder which then sends copies to individual BITNET
      subscribers.  This way only one copy of a given message has to
      cross the BITNET-Internet gateway in either direction.

      USENET subscribers see only individual messages.  All messages
      originating on the Internet side are forwarded to our USENET
      machine.  They are then posted to the appropriate newsgroup.
      Unfortunately, for gatewayed messages, the sender becomes
      "news@brl-adm".  This is currently an unavoidable side-effect of
      the software which performs the gateway function.

      As for readership, USENET has an extremely large readership - I
      would guess several thousand hosts and tens of thousands of
      readers.  The master list maintained here at BRL runs about two
      hundred fifty entries with roughly ten percent of those being
      local redistribution lists.  I don't have a good feel for the
      size of the BITNET redistribution, but I would guess it is
      roughly the same size and composition as the master list.
      Traffic runs 150K to 400K bytes per list per week on average.

1.5)  What are some useful Unix or C books?

      Mitch Wright (mitch@cirrus.com) maintains a useful list of Unix
      and C books, with descriptions and some mini-reviews.  There are
      currently 77 titles on his list.

      You can obtain a copy of this list by anonymous ftp from
      ftp.wg.omron.co.jp (133.210.4.4), where it's
      "pub/unix-faq/docs/Unix-C-Booklist".  If you can't use anonymous
      ftp, email the line "help" to "mailserv@iuvax.cs.indiana.edu" for
      instructions on retrieving things via email.

      Send additions or suggestions to mitch@cirrus.com.

1.6)  What happened to the pronunciation list that used to be part of this
      document?

      From its inception in 1989, this FAQ document included a
      comprehensive pronunciation list maintained by Maarten Litmaath
      (thanks, Maarten!).  (Does anyone know who *created* it?)

      It has been retired, since it is not really relevant to the topic
      of "Unix questions".  You can still find it as part of the
      widely-distributed "Jargon" file (maintained by Eric S. Raymond,
      eric@snark.thyrsus.com) which seems like a much more appropriate
      forum for the topic of "How do you pronounce  /* ?"

      If you'd like a copy, you can ftp one from ftp.wg.omron.co.jp
      (133.210.4.4), it's "pub/unix-faq/docs/Pronunciation-Guide".

-- 
Ted Timar - tmatimar@empress.com
Empress Software, 3100 Steeles Ave E, Markham, Ont., Canada L3R 8T3

-----------------------------

From: Ted M A Timar <tmatimar@empress.com>
Subject: Frequently Asked Questions about Unix (2/7) [Biweekly posting]
Date: 20 Nov 92 06:00:47 GMT
Expires: 18 Dec 1992 06:00:22 GMT
Followup-To: comp.unix.questions
Supersedes: <unix-faq/part2_721029617@athena.mit.edu>
NNTP-Posting-Host: pit-manager.mit.edu
X-Last-Updated: 1992/10/21
To:       info-unix@sem.brl.mil

Archive-name: unix-faq/part2
Version: $Id: part2,v 2.0 92/10/20 12:07:03 tmatimar Exp $

These seven articles contain the answers to some Frequently Asked
Questions often seen in comp.unix.questions and comp.unix.shell.
Please don't ask these questions again, they've been answered plenty
of times already - and please don't flame someone just because they may
not have read this particular posting.  Thank you.

These articles are divided approximately as follows:

      1.*) General questions.
      2.*) Relatively basic questions, likely to be asked by beginners.
      3.*) Intermediate questions.
      4.*) Advanced questions, likely to be asked by people who thought
	   they already knew all of the answers.
      5.*) Questions pertaining to the various shells, and the differences.
      6.*) An overview of Unix variants.
      7.*) An comparison of configuration management systems (RCS, SCCS).

This article includes answers to:

      2.1)  How do I remove a file whose name begins with a "-" ?
      2.2)  How do I remove a file with funny characters in the filename ?
      2.3)  How do I get a recursive directory listing?
      2.4)  How do I get the current directory into my prompt?
      2.5)  How do I read characters from the terminal in a shell script?
      2.6)  How do I rename "*.foo" to "*.bar", or change file names
              to lowercase?
      2.7)  Why do I get [some strange error message] when I
              "rsh host command" ?
      2.8)  How do I {set an environment variable, change directory} inside a
              program or shell script and have that change affect my
              current shell?
      2.9)  How do I redirect stdout and stderr separately in csh?
      2.10) How do I tell inside .cshrc if I'm a login shell?
      2.11) How do I construct a shell glob-pattern that matches all files
            except "." and ".." ?
      2.12) How do I find the last argument in a Bourne shell script?
      2.13) What's wrong with having '.' in your $PATH ?

If you're looking for the answer to, say, question 2.5, and want to skip
everything else, you can search ahead for the regular expression "^2.5)".

While these are all legitimate questions, they seem to crop up in
comp.unix.questions or comp.unix.shell on an annual basis, usually
followed by plenty of replies (only some of which are correct) and then
a period of griping about how the same questions keep coming up.  You
may also like to read the monthly article "Answers to Frequently Asked
Questions" in the newsgroup "news.announce.newusers", which will tell
you what "UNIX" stands for.

With the variety of Unix systems in the world, it's hard to guarantee
that these answers will work everywhere.  Read your local manual pages
before trying anything suggested here.  If you have suggestions or
corrections for any of these answers, please send them to to
tmatimar@empress.com.

2.1)  How do I remove a file whose name begins with a "-" ?

      Figure out some way to name the file so that it doesn't begin
      with a dash.  The simplest answer is to use

	    rm ./-filename

      (assuming "-filename" is in the current directory, of course.)
      This method of avoiding the interpretation of the "-" works with
      other commands too.

      Many commands, particularly those that have been written to use
      the "getopt(3)" argument parsing routine, accept a "--" argument
      which means "this is the last option, anything after this is not
      an option", so your version of rm might handle "rm -- -filename".
      Some versions of rm that don't use getopt() treat a single "-"
      in the same way, so you can also try "rm - -filename".

2.2)  How do I remove a file with funny characters in the filename ?

      If the 'funny character' is a '/', skip to the last part of this
      answer.  If the funny character is something else, such as a ' '
      or control character or character with the 8th bit set, keep reading.

      The classic answers are

	rm -i some*pattern*that*matches*only*the*file*you*want

	which asks you whether you want to remove each file matching
	the indicated pattern;  depending on your shell, this may not
	work if the filename has a character with the 8th bit set (the
	shell may strip that off);

      and

	rm -ri .

	which asks you whether to remove each file in the directory.
	Answer "y" to the problem file and "n" to everything else.
	Unfortunately this doesn't work with many versions of rm.  Also
	unfortunately, this will walk through every subdirectory of ".",
	so you might want to "chmod a-x" those directories temporarily
	to make them unsearchable.

	Always take a deep breath and think about what you're doing and
	double check what you typed when you use rm's "-r" flag or a
	wildcard on the command line;

      and

	find . -type f ... -ok rm '{}' \;

      where "..." is a group of predicates that uniquely identify the
      file.  One possibility is to figure out the inode number of the
      problem file (use "ls -i .") and then use

	find . -inum 12345 -ok rm '{}' \;

      or
	find . -inum 12345 -ok mv '{}' new-file-name \;
	
      "-ok" is a safety check - it will prompt you for confirmation of
      the command it's about to execute.  You can use "-exec" instead
      to avoid the prompting, if you want to live dangerously, or if
      you suspect that the filename may contain a funny character
      sequence that will mess up your screen when printed.

      What if the filename has a '/' in it?

      These files really are special cases, and can only be created by
      buggy kernel code (typically by implementations of NFS that don't
      filter out illegal characters in file names from remote
      machines.)  The first thing to do is to try to understand exactly
      why this problem is so strange.

      Recall that Unix directories are simply pairs of filenames and
      inode numbers.  A directory essentially contains information
      like this:

	filename  inode

	file1	  12345
	file2.c	  12349
	file3     12347

      Theoretically, '/' and '\0' are the only two characters that
      cannot appear in a filename - '/' because it's used to separate
      directories and files, and '\0' because it terminates a filename.

      Unfortunately some implementations of NFS will blithely create
      filenames with embedded slashes in response to requests from
      remote machines.  For instance, this could happen when someone on
      a Mac or other non-Unix machine decides to create a remote NFS
      file on your Unix machine with the date in the filename.  Your
      Unix directory then has this in it:

	filename  inode

	91/02/07  12357

      No amount of messing around with 'find' or 'rm' as described
      above will delete this file, since those utilities and all other
      Unix programs, are forced to interpret the '/' in the normal way.

      Any ordinary program will eventually try to do
      unlink("91/02/07"), which as far as the kernel is concerned means
      "unlink the file 07 in the subdirectory 02 of directory 91", but
      that's not what we have - we have a *FILE* named "91/02/07" in
      the current directory.  This is a subtle but crucial distinction.

      What can you do in this case?  The first thing to try is to
      return to the Mac that created this crummy entry, and see if you
      can convince it and your local NFS daemon to rename the file to
      something without slashes.

      If that doesn't work or isn't possible, you'll need help from
      your system manager, who will have to try the one of the
      following.  Use "ls -i" to find the inode number of this bogus
      file, then unmount the file system and use "clri" to clear the
      inode, and "fsck" the file system with your fingers crossed.
      This destroys the information in the file.  If you want to keep
      it, you can try:

	create a new directory in the same parent directory as the one
	containing the bad file name;

	move everything you can (i.e. everything but the file with the
	bad name) from the old directory to the new one;

	do "ls -id" on the directory containing the file with the bad
	name to get its inumber;

	umount the file system;

	"clri" the directory containing the file with the bad name;

	"fsck" the file system.

      Then, to find the file,

	remount the file system;

	rename the directory you created to have the name of the old
	directory (since the old directory should have been blown away
	by "fsck")

	move the file out of "lost+found" into the directory with a
	better name.

      Alternatively, you can patch the directory the hard way by
      crawling around in the raw file system.  Use "fsdb", if you
      have it.

2.3)  How do I get a recursive directory listing?

      One of the following may do what you want:

	ls -R 			(not all versions of "ls" have -R)
	find . -print		(should work everywhere)
	du -a .			(shows you both the name and size)

      If you're looking for a wildcard pattern that will match all ".c"
      files in this directory and below, you won't find one, but you
      can use

	% some-command `find . -name '*.c' -print`

      "find" is a powerful program.  Learn about it.

2.4)  How do I get the current directory into my prompt?

      It depends which shell you are using.  It's easy with some
      shells, hard or impossible with others.

      C Shell (csh):
	Put this in your .cshrc - customize the prompt variable the
	way you want.

	    alias setprompt 'set prompt="${cwd}% "'
	    setprompt		# to set the initial prompt
	    alias cd 'chdir \!* && setprompt'
	
	If you use pushd and popd, you'll also need

	    alias pushd 'pushd \!* && setprompt'
	    alias popd  'popd  \!* && setprompt'

	Some C shells don't keep a $cwd variable - you can use
	`pwd` instead.

	If you just want the last component of the current directory
	in your prompt ("mail% " instead of "/usr/spool/mail% ")
	you can use

	    alias setprompt 'set prompt="$cwd:t% "'
	
	Some older csh's get the meaning of && and || reversed.
	Try doing:

	    false && echo bug

	If it prints "bug", you need to switch && and || (and get
	a better version of csh.)

      Bourne Shell (sh):

	If you have a newer version of the Bourne Shell (SVR2 or newer)
	you can use a shell function to make your own command, "xcd" say:

	    xcd() { cd $* ; PS1="`pwd` $ "; }

	If you have an older Bourne shell, it's complicated but not
	impossible.  Here's one way.  Add this to your .profile file:

		LOGIN_SHELL=$$ export LOGIN_SHELL
		CMDFILE=/tmp/cd.$$ export CMDFILE
		# 16 is SIGURG, pick a signal that's not likely to be used
		PROMPTSIG=16 export PROMPTSIG
		trap '. $CMDFILE' $PROMPTSIG

	and then put this executable script (without the indentation!),
	let's call it "xcd", somewhere in your PATH

		: xcd directory - change directory and set prompt
		: by signalling the login shell to read a command file
		cat >${CMDFILE?"not set"} <<EOF
		cd $1
		PS1="\`pwd\`$ "
		EOF
		kill -${PROMPTSIG?"not set"} ${LOGIN_SHELL?"not set"}

	Now change directories with "xcd /some/dir".

      Korn Shell (ksh):

	Put this in your .profile file:
		PS1='$PWD $ '
	
	If you just want the last component of the directory, use
		PS1='${PWD##*/} $ '

      T C shell (tcsh)

	Tcsh is a popular enhanced version of csh with some extra
	builtin variables (and many other features):

	    %~		the current directory, using ~ for $HOME
	    %d or %/	the full pathname of the current directory
	    %c or %.	the trailing component of the current directory

	so you can do

	    set prompt='%~ '

      BASH (FSF's "Bourne Again SHell")
	
	\w in $PS1 gives the full pathname of the current directory,
	with ~ expansion for $HOME;  \W gives the basename of
	the current directory.  So, in addition to the above sh and
	ksh solutions, you could use

	    PS1='\w $ '	
	or
	    PS1='\W $ '

2.5)  How do I read characters from the terminal in a shell script?

      In sh, use read.  It is most common to use a loop like

	    while read line
	    do
		    ...
	    done

      In csh, use $< like this:
	
	    while ( 1 )
		set line = "$<"
		if ( "$line" == "" ) break
		...
	    end

      Unfortunately csh has no way of distinguishing between a blank
      line and an end-of-file.

      If you're using sh and want to read a *single* character from the
      terminal, you can try something like

	    echo -n "Enter a character: "
	    stty cbreak		# or  stty raw
	    readchar=`dd if=/dev/tty bs=1 count=1 2>/dev/null`
	    stty -cbreak

	    echo "Thank you for typing a $readchar ."

2.6)  How do I rename "*.foo" to "*.bar", or change file names to lowercase?
	
      Why doesn't "mv *.foo *.bar" work?  Think about how the shell
      expands wildcards.   "*.foo" and "*.bar" are expanded before the
      mv command ever sees the arguments.  Depending on your shell,
      this can fail in a couple of ways.  CSH prints "No match."
      because it can't match "*.bar".  SH executes "mv a.foo b.foo
      c.foo *.bar", which will only succeed if you happen to have a
      single directory named "*.bar", which is very unlikely and almost
      certainly not what you had in mind.

      Depending on your shell, you can do it with a loop to "mv" each
      file individually.  If your system has "basename", you can use:

      C Shell:
	foreach f ( *.foo )
	    set base=`basename $f .foo`
	    mv $f $base.bar
	end

      Bourne Shell:
	for f in *.foo; do
	    base=`basename $f .foo`
	    mv $f $base.bar
	done

      Some shells have their own variable substitution features, so
      instead of using "basename", you can use simpler loops like:

      C Shell:

	foreach f ( *.foo )
	    mv $f $f:r.bar
	end

      Korn Shell:

	for f in *.foo; do
	    mv $f ${f%foo}bar
	done

      If you don't have "basename" or want to do something like
      renaming foo.* to bar.*, you can use something like "sed" to
      strip apart the original file name in other ways, but the general
      looping idea is the same.  You can also convert file names into
      "mv" commands with 'sed', and hand the commands off to "sh" for
      execution.  Try

	ls -d *.foo | sed -e 's/.*/mv & &/' -e 's/foo$/bar/' | sh

      A program by Vladimir Lanin called "mmv" that does this job
      nicely was posted to comp.sources.unix (Volume 21, issues 87 and
      88) in April 1990.  It lets you use

	mmv '*.foo' '=1.bar'

      Shell loops like the above can also be used to translate file
      names from upper to lower case or vice versa.  You could use
      something like this to rename uppercase files to lowercase:

	C Shell:
	    foreach f ( * )
		mv $f `echo $f | tr '[A-Z]' '[a-z]'`
	    end
	Bourne Shell:
	    for f in *; do
		mv $f `echo $f | tr '[A-Z]' '[a-z]'`
	    done
	Korn Shell:
	    typeset -l l
	    for f in *; do
		l="$f"
		mv $f $l
	    done

      If you wanted to be really thorough and handle files with `funny'
      names (embedded blanks or whatever) you'd need to use

	Bourne Shell:

	    for f in *; do
	      g=`expr "xxx$f" : 'xxx\(.*\)' | tr '[A-Z]' '[a-z]'`
	      mv "$f" "$g"
	    done

      The `expr' command will always print the filename, even if it
      equals `-n' or if it contains a System V escape sequence like `\c'.

      Some versions of "tr" require the [ and ], some don't.  It
      happens to be harmless to include them in this particular
      example; versions of tr that don't want the [] will conveniently
      think they are supposed to translate '[' to '[' and ']' to ']'.

      If you have the "perl" language installed, you may find this
      rename script by Larry Wall very useful.  It can be used to
      accomplish a wide variety of filename changes.

	#!/usr/bin/perl
	#
	# rename script examples from lwall:
	#       rename 's/\.orig$//' *.orig
	#       rename 'y/A-Z/a-z/ unless /^Make/' *
	#       rename '$_ .= ".bad"' *.f
	#       rename 'print "$_: "; s/foo/bar/ if <stdin> =~ /^y/i' *

	$op = shift;
	for (@ARGV) {
	    $was = $_;
	    eval $op;
	    die $@ if $@;
	    rename($was,$_) unless $was eq $_;
	}

2.7)  Why do I get [some strange error message] when I "rsh host command" ?

      (We're talking about the remote shell program "rsh" or sometimes
      "remsh" or "remote"; on some machines, there is a restricted shell
      called "rsh", which is a different thing.)

      If your remote account uses the C shell, the remote host will
      fire up a C shell to execute 'command' for you, and that shell
      will read your remote .cshrc file.  Perhaps your .cshrc contains
      a "stty", "biff" or some other command that isn't appropriate for
      a non-interactive shell.  The unexpected output or error message
      from these commands can screw up your rsh in odd ways.

      Here's an example.  Suppose you have

	stty erase ^H
	biff y

      in your .cshrc file.  You'll get some odd messages like this.

	% rsh some-machine date
	stty: : Can't assign requested address
	Where are you?
	Tue Oct  1 09:24:45 EST 1991

      You might also get similar errors when running certain "at" or
      "cron" jobs that also read your .cshrc file.

      Fortunately, the fix is simple.  There are, quite possibly, a
      whole *bunch* of operations in your ".cshrc" (e.g., "set
      history=N") that are simply not worth doing except in interactive
      shells.  What you do is surround them in your ".cshrc" with:

	    if ( $?prompt ) then
		    operations....
	    endif

      and, since in a non-interactive shell "prompt" won't be set, the
      operations in question will only be done in interactive shells.

      You may also wish to move some commands to your .login file; if
      those commands only need to be done when a login session starts
      up (checking for new mail, unread news and so on) it's better to
      have them in the .login file.

2.8)  How do I {set an environment variable, change directory} inside
      a program or shell script and have that change affect my
      current shell?

      In general, you can't, at least not without making special
      arrangements.  When a child process is created, it inherits a
      copy of its parent's variables (and current directory).  The
      child can change these values all it wants but the changes won't
      affect the parent shell, since the child is changing a copy of
      the original data.

      Some special arrangements are possible.  Your child process could
      write out the changed variables, if the parent was prepared to
      read the output and interpret it as commands to set its own
      variables.

      Also, shells can arrange to run other shell scripts in the
      context of the current shell, rather than in a child process, so
      that changes will affect the original shell.

      For instance, if you have a C shell script named "myscript":

	cd /very/long/path
	setenv PATH /something:/something-else

      or the equivalent Bourne or Korn shell script

	cd /very/long/path
	PATH=/something:/something-else export PATH

      and try to run "myscript" from your shell, your shell will fork
      and run the shell script in a subprocess.  The subprocess is also
      running the shell; when it sees the "cd" command it changes *its*
      current directory, and when it sees the "setenv" command it
      changes *its* environment, but neither has any effect on the
      current directory of the shell at which you're typing (your login
      shell, let's say).

      In order to get your login shell to execute the script (without
      forking) you have to use the "." command (for the Bourne or Korn
      shells) or the "source" command (for the C shell).  I.e. you type

	. myscript

      to the Bourne or Korn shells, or

	source myscript

      to the C shell.

      If all you are trying to do is change directory or set an
      environment variable, it will probably be simpler to use a C
      shell alias or Bourne/Korn shell function.  See the "how do I get
      the current directory into my prompt" section of this article for
      some examples.

2.9)  How do I redirect stdout and stderr separately in csh?

      In csh, you can redirect stdout with ">", or stdout and stderr
      together with ">&" but there is no direct way to redirect stderr
      only.  The best you can do is

	( command >stdout_file ) >&stderr_file

      which runs "command" in a subshell;  stdout is redirected inside
      the subshell to stdout_file, and both stdout and stderr from the
      subshell are redirected to stderr_file, but by this point stdout
      has already been redirected so only stderr actually winds up in
      stderr_file.

      Sometimes it's easier to let sh do the work for you.

	sh -c 'command >stdout_file 2>stderr_file'

2.10) How do I tell inside .cshrc if I'm a login shell?

      When people ask this, they usually mean either

	How can I tell if it's an interactive shell?  or
	How can I tell if it's a top-level shell?

      You could perhaps determine if your shell truly is a login shell
      (i.e. is going to source ".login" after it is done with ".cshrc")
      by fooling around with "ps" and "$$".  Login shells generally
      have names that begin with a '-'.  If you're really interested in
      the other two questions, here's one way you can organize your
      .cshrc to find out.

	if (! $?CSHLEVEL) then
		#
		# This is a "top-level" shell,
		# perhaps a login shell, perhaps a shell started up by
		# 'rsh machine some-command'
		# This is where we should set PATH and anything else we
		# want to apply to every one of our shells.
		#
		setenv      CSHLEVEL        0
		set home = ~username        # just to be sure
		source ~/.env               # environment stuff we always want
	else
		#
		# This shell is a child of one of our other shells so
		# we don't need to set all the environment variables again.
		#
		set tmp = $CSHLEVEL
		@ tmp++
		setenv      CSHLEVEL        $tmp
	endif

	# Exit from .cshrc if not interactive, e.g. under rsh
	if (! $?prompt) exit

	# Here we could set the prompt or aliases that would be useful
	# for interactive shells only.

	source ~/.aliases

2.11) How do I construct a shell glob-pattern that matches all files
      except "." and ".." ?

      You'd think this would be easy.

      *        Matches all files that don't begin with a ".";

      .*	     Matches all files that do begin with a ".", but
	     this includes the special entries "." and "..",
	     which often you don't want;

      .[!.]*   (Newer shells only; some shells use a "^" instead of
	     the "!"; POSIX shells must accept the "!", but may
	     accept a "^" as well; all portable applications shall
	     not use an unquoted "^" immediately following the "[")

	     Matches all files that begin with a "." and are
	     followed by a non-"."; unfortunately this will miss
	     "..foo";

      .??*     Matches files that begin with a "." and which are
	     at least 3 characters long.  This neatly avoids
	     "." and "..", but also misses ".a" .

      So to match all files except "." and ".." safely you have to use
      3 patterns (if you don't have filenames like ".a" you can leave
      out the first):

	.[!.]* .??* *

      Alternatively you could employ an external program or two and use
      backquote substitution.  This is pretty good:

      `ls -a | sed -e '/^\.$/d' -e '/^\.\.$/d'`

	(or `ls -A` in some Unix versions)

      but even it will mess up on files with newlines, IFS characters
      or wildcards in their names.

2.12) How do I find the last argument in a Bourne shell script?

      Answer by:
	Martin Weitzel <@mikros.systemware.de:martin@mwtech.uucp>
	Maarten Litmaath <maart@nat.vu.nl>

      If you are sure the number of arguments is at most 9, you can use:

	eval last=\${$#}

      In POSIX-compatible shells it works for ANY number of arguments.
      The following works always too:

	for last
	do
		:
	done

      This can be generalized as follows:

	for i
	do
		third_last=$second_last
		second_last=$last
		last=$i
	done

      Now suppose you want to REMOVE the last argument from the list,
      or REVERSE the argument list, or ACCESS the N-th argument
      directly, whatever N may be.  Here is a basis of how to do it,
      using only built-in shell constructs, without creating subprocesses:

	t0= u0= rest='1 2 3 4 5 6 7 8 9' argv=

	for h in '' $rest
	do
		for t in "$t0" $rest
		do
			for u in $u0 $rest
			do
				case $# in
				0)
					break 3
				esac
				eval argv$h$t$u=\$1
				argv="$argv \"\$argv$h$t$u\""	# (1)
				shift
			done
			u0=0
		done
		t0=0
	done

	# now restore the arguments
	eval set x "$argv"					# (2)
	shift

      This example works for the first 999 arguments.  Enough?
      Take a good look at the lines marked (1) and (2) and convince
      yourself that the original arguments are restored indeed, no
      matter what funny characters they contain!

      To find the N-th argument now you can use this:

	eval argN=\$argv$N

      To reverse the arguments the line marked (1) must be changed to:

	argv="\"\$argv$h$t$u\" $argv"

      How to remove the last argument is left as an exercise.

      If you allow subprocesses as well, possibly executing nonbuilt-in
      commands, the `argvN' variables can be set up more easily:

	N=1

	for i
	do
		eval argv$N=\$i
		N=`expr $N + 1`
	done

      To reverse the arguments there is still a simpler method, that
      even does not create subprocesses.  This approach can also be
      taken if you want to delete e.g. the last argument, but in that
      case you cannot refer directly to the N-th argument any more,
      because the `argvN' variables are set up in reverse order:

	argv=

	for i
	do
		eval argv$#=\$i
		argv="\"\$argv$#\" $argv"
		shift
	done

	eval set x "$argv"
	shift

2.13) What's wrong with having '.' in your $PATH ?

      A bit of background: the PATH environment variable is a list of
      directories separated by colons.  When you type a command name
      without giving an explicit path (e.g. you type "ls", rather than
      "/bin/ls") your shell searches each directory in the PATH list in
      order, looking for an executable file by that name, and the shell
      will run the first matching program it finds.

      One of the directories in the PATH list can be the current
      directory "." .  It is also permissible to use an empty directory
      name in the PATH list to indicate the current directory.  Both of
      these are equivalent

      for csh users:

	setenv PATH :/usr/ucb:/bin:/usr/bin
	setenv PATH .:/usr/ucb:/bin:/usr/bin

      for sh or ksh users

	PATH=:/usr/ucb:/bin:/usr/bin export PATH
	PATH=.:/usr/ucb:/bin:/usr/bin export PATH

      Having "." somewhere in the PATH is convenient - you can type
      "a.out" instead of "./a.out" to run programs in the current
      directory.  But there's a catch.

      Consider what happens in the case  where "." is the first entry
      in the PATH.  Suppose your current directory is a publically-
      writable one, such as "/tmp".  If there just happens to be a
      program named "/tmp/ls" left there by some other user, and you
      type "ls" (intending, of course, to run the normal "/bin/ls"
      program), your shell will instead run "./ls", the other user's
      program.  Needless to say, the results of running an unknown
      program like this might surprise you.

      It's slightly better to have "." at the end of the PATH:

	setenv PATH /usr/ucb:/bin:/usr/bin:.

      Now if you're in /tmp and you type "ls", the shell will
      search /usr/ucb, /bin and /usr/bin for a program named
      "ls" before it gets around to looking in ".", and there
      is less risk of inadvertently running some other user's
      "ls" program.  This isn't 100% secure though - if you're
      a clumsy typist and some day type "sl -l" instead of "ls -l",
      you run the risk of running "./sl", if there is one.
      Some "clever" programmer could anticipate common typing
      mistakes and leave programs by those names scattered
      throughout public directories.  Beware.

      Many seasoned Unix users get by just fine without having
      "." in the PATH at all:

	setenv PATH /usr/ucb:/bin:/usr/bin

      If you do this, you'll need to type "./program" instead
      of "program" to run programs in the current directory, but
      the increase in security is probably worth it.

-- 
Ted Timar - tmatimar@empress.com
Empress Software, 3100 Steeles Ave E, Markham, Ont., Canada L3R 8T3

-----------------------------

From: Ted M A Timar <tmatimar@empress.com>
Subject: Frequently Asked Questions about Unix (4/7) [Biweekly posting]
Date: 20 Nov 92 06:00:49 GMT
Expires: 18 Dec 1992 06:00:22 GMT
Followup-To: comp.unix.questions
Supersedes: <unix-faq/part4_721029617@athena.mit.edu>
NNTP-Posting-Host: pit-manager.mit.edu
X-Last-Updated: 1992/10/21
To:       info-unix@sem.brl.mil

Archive-name: unix-faq/part4
Version: $Id: part4,v 2.0 92/10/20 12:07:10 tmatimar Exp $

These seven articles contain the answers to some Frequently Asked
Questions often seen in comp.unix.questions and comp.unix.shell.
Please don't ask these questions again, they've been answered plenty
of times already - and please don't flame someone just because they may
not have read this particular posting.  Thank you.

These articles are divided approximately as follows:

      1.*) General questions.
      2.*) Relatively basic questions, likely to be asked by beginners.
      3.*) Intermediate questions.
      4.*) Advanced questions, likely to be asked by people who thought
	   they already knew all of the answers.
      5.*) Questions pertaining to the various shells, and the differences.
      6.*) An overview of Unix variants.
      7.*) An comparison of configuration management systems (RCS, SCCS).

This article includes answers to:

      4.1)  How do I read characters from a terminal without requiring the user
              to hit RETURN?
      4.2)  How do I check to see if there are characters to be read without
              actually reading?
      4.3)  How do I find the name of an open file?
      4.4)  How can an executing program determine its own pathname?
      4.5)  How do I use popen() to open a process for reading AND writing?
      4.6)  How do I sleep() in a C program for less than one second?
      4.7)  How can I get setuid shell scripts to work?
      4.8)  How can I find out which user or process has a file open or is using
            a particular file system (so that I can unmount it?)
      4.9)  How do I keep track of people who are fingering me?
      4.10) Is it possible to reconnect a process to a terminal after it has
            been disconnected, e.g. after starting a program in the background
            and logging out?
      4.11) Is it possible to "spy" on a terminal, displaying the output
            that's appearing on it on another terminal?

If you're looking for the answer to, say, question 4.5, and want to skip
everything else, you can search ahead for the regular expression "^4.5)".

While these are all legitimate questions, they seem to crop up in
comp.unix.questions or comp.unix.shell on an annual basis, usually
followed by plenty of replies (only some of which are correct) and then
a period of griping about how the same questions keep coming up.  You
may also like to read the monthly article "Answers to Frequently Asked
Questions" in the newsgroup "news.announce.newusers", which will tell
you what "UNIX" stands for.

With the variety of Unix systems in the world, it's hard to guarantee
that these answers will work everywhere.  Read your local manual pages
before trying anything suggested here.  If you have suggestions or
corrections for any of these answers, please send them to to
tmatimar@empress.com.

4.1)  How do I read characters from a terminal without requiring the user
      to hit RETURN?

      Check out cbreak mode in BSD, ~ICANON mode in SysV.

      If you don't want to tackle setting the terminal parameters
      yourself (using the "ioctl(2)" system call) you can let the stty
      program do the work - but this is slow and inefficient, and you
      should change the code to do it right some time:

      #include <stdio.h>
      main()
      {
	    int c;

	    printf("Hit any character to continue\n");
	    /*
	     * ioctl() would be better here; only lazy
	     * programmers do it this way:
	     */
	    system("/bin/stty cbreak");        /* or "stty raw" */
	    c = getchar();
	    system("/bin/stty -cbreak");
	    printf("Thank you for typing %c.\n", c);

	    exit(0);
      }

      You might like to check out the documentation for the "curses"
      library of portable screen functions.  Often if you're interested
      in single-character I/O like this, you're also interested in
      doing some sort of screen display control, and the curses library
      provides various portable routines for both functions.

4.2)  How do I check to see if there are characters to be read without
      actually reading?

      Certain versions of UNIX provide ways to check whether characters
      are currently available to be read from a file descriptor.  In
      BSD, you can use select(2).  You can also use the FIONREAD ioctl
      (see tty(4)), which returns the number of characters waiting to
      be read, but only works on terminals, pipes and sockets.  In
      System V Release 3, you can use poll(2), but that only works on
      streams.  In Xenix - and therefore Unix SysV r3.2 and later - the
      rdchk() system call reports whether a read() call on a given file
      descriptor will block.

      There is no way to check whether characters are available to be
      read from a FILE pointer.  (You could poke around inside stdio
      data structures to see if the input buffer is nonempty, but that
      wouldn't work since you'd have no way of knowing what will happen
      the next time you try to fill the buffer.)

      Sometimes people ask this question with the intention of writing
	    if (characters available from fd)
		    read(fd, buf, sizeof buf);
      in order to get the effect of a nonblocking read.  This is not
      the best way to do this, because it is possible that characters
      will be available when you test for availability, but will no
      longer be available when you call read.  Instead, set the
      O_NDELAY flag (which is also called FNDELAY under BSD) using the
      F_SETFL option of fcntl(2).  Older systems (Version 7, 4.1 BSD)
      don't have O_NDELAY; on these systems the closest you can get to
      a nonblocking read is to use alarm(2) to time out the read.

4.3)  How do I find the name of an open file?

      In general, this is too difficult.  The file descriptor may
      be attached to a pipe or pty, in which case it has no name.
      It may be attached to a file that has been removed.  It may
      have multiple names, due to either hard or symbolic links.

      If you really need to do this, and be sure you think long
      and hard about it and have decided that you have no choice,
      you can use find with the -inum and possibly -xdev option,
      or you can use ncheck, or you can recreate the functionality
      of one of these within your program.  Just realize that
      searching a 600 megabyte filesystem for a file that may not
      even exist is going to take some time.

4.4)  How can an executing program determine its own pathname?

      Your program can look at argv[0]; if it begins with a "/", it is
      probably the absolute pathname to your program, otherwise your
      program can look at every directory named in the environment
      variable PATH and try to find the first one that contains an
      executable file whose name matches your program's argv[0] (which
      by convention is the name of the file being executed).  By
      concatenating that directory and the value of argv[0] you'd
      probably have the right name.

      You can't really be sure though, since it is quite legal for one
      program to exec() another with any value of argv[0] it desires.
      It is merely a convention that new programs are exec'd with the
      executable file name in argv[0].

      For instance, purely a hypothetical example:
	
	#include <stdio.h>
	main()
	{
	    execl("/usr/games/rogue", "vi Thesis", (char *)NULL);
	}

      The executed program thinks its name (its argv[0] value) is
      "vi Thesis".   (Certain other programs might also think that
      the name of the program you're currently running is "vi Thesis",
      but of course this is just a hypothetical example, don't
      try it yourself :-)

4.5)  How do I use popen() to open a process for reading AND writing?

      The problem with trying to pipe both input and output to an
      arbitrary slave process is that deadlock can occur, if both
      processes are waiting for not-yet-generated input at the same
      time.  Deadlock can be avoided only by having BOTH sides follow a
      strict deadlock-free protocol, but since that requires
      cooperation from the processes it is inappropriate for a
      popen()-like library function.

      The 'expect' distribution includes a library of functions that a
      C programmer can call directly.  One of the functions does the
      equivalent of a popen for both reading and writing.  It uses ptys
      rather than pipes, and has no deadlock problem.  It's portable to
      both BSD and SV.  See the next answer for more about 'expect'.

4.6)  How do I sleep() in a C program for less than one second?

      The first thing you need to be aware of is that all you can
      specify is a MINIMUM amount of delay; the actual delay will
      depend on scheduling issues such as system load, and could be
      arbitrarily large if you're unlucky.

      There is no standard library function that you can count on in
      all environments for "napping" (the usual name for short
      sleeps).  Some environments supply a "usleep(n)" function which
      suspends execution for n microseconds.  If your environment
      doesn't support usleep(), here are a couple of implementations
      for BSD and System V environments.

      The following code is adapted from Doug Gwyn's System V emulation
      support for 4BSD and exploits the 4BSD select() system call.
      Doug originally called it 'nap()'; you probably want to call it
      "usleep()";

      /*
	    usleep -- support routine for 4.2BSD system call emulations
	    last edit:	29-Oct-1984	D A Gwyn
      */

      extern int	select();

      int
      usleep( usec )				/* returns 0 if ok, else -1 */
	    long		usec;		/* delay in microseconds */
	    {
	    static struct			/* `timeval' */
		    {
		    long	tv_sec;		/* seconds */
		    long	tv_usec;	/* microsecs */
		    }	delay;		/* _select() timeout */

	    delay.tv_sec = usec / 1000000L;
	    delay.tv_usec = usec % 1000000L;

	    return select( 0, (long *)0, (long *)0, (long *)0, &delay );
	    }

      On System V you might do it this way:

      /*
      subseconds sleeps for System V - or anything that has poll()
      Don Libes, 4/1/1991

      The BSD analog to this function is defined in terms of
      microseconds while poll() is defined in terms of milliseconds.
      For compatibility, this function provides accuracy "over the long
      run" by truncating actual requests to milliseconds and
      accumulating microseconds across calls with the idea that you are
      probably calling it in a tight loop, and that over the long run,
      the error will even out.

      If you aren't calling it in a tight loop, then you almost
      certainly aren't making microsecond-resolution requests anyway,
      in which case you don't care about microseconds.  And if you did,
      you wouldn't be using UNIX anyway because random system
      indigestion (i.e., scheduling) can make mincemeat out of any
      timing code.

      Returns 0 if successful timeout, -1 if unsuccessful.

      */

      #include <poll.h>

      int
      usleep(usec)
      unsigned int usec;		/* microseconds */
      {
	    static subtotal = 0;	/* microseconds */
	    int msec;			/* milliseconds */

	    /* 'foo' is only here because some versions of 5.3 have
	     * a bug where the first argument to poll() is checked
	     * for a valid memory address even if the second argument is 0.
	     */
	    struct pollfd foo;

	    subtotal += usec;
	    /* if less then 1 msec request, do nothing but remember it */
	    if (subtotal < 1000) return(0);
	    msec = subtotal/1000;
	    subtotal = subtotal%1000;
	    return poll(&foo,(unsigned long)0,msec);
      }

      Another possibility for nap()ing on System V, and probably other
      non-BSD Unices is Jon Zeeff's s5nap package, posted to
      comp.sources.misc, volume 4.  It does require a installing a
      device driver, but works flawlessly once installed.  (Its
      resolution is limited to the kernel HZ value, since it uses the
      kernel delay() routine.)

4.7)  How can I get setuid shell scripts to work?

      [ This is a long answer, but it's a complicated and frequently-asked
        question.  Thanks to Maarten Litmaath for this answer, and
        for the "indir" program mentioned below. ]

      Let us first assume you are on a UNIX variant (e.g. 4.3BSD or
      SunOS) that knows about so-called `executable shell scripts'.
      Such a script must start with a line like:

	#!/bin/sh

      The script is called `executable' because just like a real (binary)
      executable it starts with a so-called `magic number' indicating
      the type of the executable.  In our case this number is `#!' and
      the OS takes the rest of the first line as the interpreter for
      the script, possibly followed by 1 initial option like:

	#!/bin/sed -f

      Suppose this script is called `foo' and is found in /bin,
      then if you type:

	foo arg1 arg2 arg3

      the OS will rearrange things as though you had typed:

	/bin/sed -f /bin/foo arg1 arg2 arg3

      There is one difference though: if the setuid permission bit for
      `foo' is set, it will be honored in the first form of the
      command; if you really type the second form, the OS will honor
      the permission bits of /bin/sed, which is not setuid, of course.

      ----------

      OK, but what if my shell script does NOT start with such a `#!'
      line or my OS does not know about it?

      Well, if the shell (or anybody else) tries to execute it, the OS
      will return an error indication, as the file does not start with
      a valid magic number.  Upon receiving this indication the shell
      ASSUMES the file to be a shell script and gives it another try:

	/bin/sh shell_script arguments

      But we have already seen that a setuid bit on `shell_script' will
      NOT be honored in this case!

      ----------

      Right, but what about the security risks of setuid shell scripts?

      Well, suppose the script is called `/etc/setuid_script', starting
      with:

	#!/bin/sh
	
      Now let us see what happens if we issue the following commands:

	$ cd /tmp
	$ ln /etc/setuid_script -i
	$ PATH=.
	$ -i

      We know the last command will be rearranged to:

	/bin/sh -i

      But this command will give us an interactive shell, setuid to the
      owner of the script!
      Fortunately this security hole can easily be closed by making the
      first line:

	#!/bin/sh -

      The `-' signals the end of the option list: the next argument `-i'
      will be taken as the name of the file to read commands from, just
      like it should!

      ---------

      There are more serious problems though:

	$ cd /tmp
	$ ln /etc/setuid_script temp
	$ nice -20 temp &
	$ mv my_script temp

      The third command will be rearranged to:

	nice -20 /bin/sh - temp

      As this command runs so slowly, the fourth command might be able
      to replace the original `temp' with `my_script' BEFORE `temp' is
      opened by the shell!  There are 4 ways to fix this security hole:

	1)  let the OS start setuid scripts in a different, secure way
	    - System V R4 and 4.4BSD use the /dev/fd driver to pass the
	    interpreter a file descriptor for the script

	2)  let the script be interpreted indirectly, through a frontend
	    that makes sure everything is all right before starting the
	    real interpreter - if you use the `indir' program from
	    comp.sources.unix the setuid script will look like this:

		#!/bin/indir -u
		#?/bin/sh /etc/setuid_script

	3)  make a `binary wrapper': a real executable that is setuid and
	    whose only task is to execute the interpreter with the name of
	    the script as an argument

	4)  make a general `setuid script server' that tries to locate the
	    requested `service' in a database of valid scripts and upon
	    success will start the right interpreter with the right
	    arguments.

      ---------

      Now that we have made sure the right file gets interpreted, are
      there any risks left?

      Certainly!  For shell scripts you must not forget to set the PATH
      variable to a safe path explicitly.  Can you figure out why?
      Also there is the IFS variable that might cause trouble if not
      set properly.  Other environment variables might turn out to
      compromise security as well, e.g. SHELL...  Furthermore you must
      make sure the commands in the script do not allow interactive
      shell escapes!  Then there is the umask which may have been set
      to something strange...

      Etcetera.  You should realise that a setuid script `inherits' all
      the bugs and security risks of the commands that it calls!

      All in all we get the impression setuid shell scripts are quite a
      risky business!  You may be better off writing a C program instead!

4.8)  How can I find out which user or process has a file open or is using
      a particular file system (so that I can unmount it?)

      Use fuser (system V), fstat (BSD), ofiles (public domain) or
      pff (public domain).  These programs will tell you various things
      about processes using particular files.

      A port of the 4.3 BSD fstat to Dynix, SunOS and Ultrix
      can be found in archives of comp.sources.unix, volume 18.

      pff is part of the kstuff package, and works on quite a few systems.
      Instructions for obtaining kstuff are provided in question 3.10.

4.9)  How do I keep track of people who are fingering me?

      Generally, you can't find out the userid of someone who is
      fingering you from a remote machine.  You may be able to
      find out which machine the remote request is coming from.
      One possibility, if your system supports it and assuming
      the finger daemon doesn't object, is to make your .plan file a
      "named pipe" instead of a plain file.  (Use 'mknod' to do this.)

      You can then start up a program that will open your .plan file
      for writing; the open will block until some other process (namely
      fingerd) opens the .plan for reading.  Now you can whatever you
      want through this pipe, which lets you show different .plan
      information every time someone fingers you.

      Of course, this may not work at all if your system doesn't
      support named pipes or if your local fingerd insists
      on having plain .plan files.

      Your program can also take the opportunity to look at the output
      of "netstat" and spot where an incoming finger connection is
      coming from, but this won't get you the remote user.

      Getting the remote userid would require that the remote site be
      running an identity service such as RFC 931.  There are now three
      RFC 931 implementations for popular BSD machines, and several
      applications (such as the wuarchive ftpd) supporting the server.
      For more information join the rfc931-users mailing list,
      rfc931-users-request@kramden.acf.nyu.edu.

      There are two caveats relating to this answer.  The first is that
      many NFS systems won't allow the recognize the named pipe
      correctly.  This means that trying to read the pipe on another
      machine will either block until it times out, or see it as a
      zero-length file, and never print it.

      The second problem is that on many systems, fingerd checks that
      the .plan file contains data (and is readable) before trying to
      read it.  This will not cause remote fingers to miss your .plan
      file entirely.

4.10) Is it possible to reconnect a process to a terminal after it has
      been disconnected, e.g. after starting a program in the background
      and logging out?

      Most variants of Unix do not support "detaching" and "attaching"
      processes, as operating systems such as VMS and Multics support.
      However, there are two freely redistributable packages which can
      be used to start processes in such a way that they can be later
      reattached to a terminal.

      The first is "screen," which is described in the
      comp.sources.unix archives as "Screen, multiple windows on a CRT"
      (see the "screen-3.2" package in comp.sources.misc, volume 28.)
      This package will run on at least BSD, System V r3.2 and SCO UNIX.

      The second is "pty," which is described in the comp.sources.unix
      archives as a package to "Run a program under a pty session" (see
      "pty" in volume 23).  pty is designed for use under BSD-like
      system only.

      Neither of these packages is retroactive, i.e. you must have
      started a process under screen or pty in order to be able to
      detach and reattach it.

4.11) Is it possible to "spy" on a terminal, displaying the output
      that's appearing on it on another terminal?

      There are a few different ways you can do this, although none
      of them is perfect:

      * kibitz allows two (or more) people to interact with a shell
        (or any arbitary program).  Uses include:

	- watching or aiding another person's terminal session;
	- recording a conversation while retaining the ability to
	  scroll backwards, save the conversation, or even edit it
	  while in progress;
	- teaming up on games, document editing, or other cooperative
	  tasks where each person has strengths and weakness that
	  complement one another.

        kibitz comes as part of the expect distribution.  See question 3.9.

        kibitz requires permission from the person to be spyed upon.  To
        spy without permission requires less pleasant approaches:

      * You can write a program that grovels through Kernel structures
        and watches the output buffer for the terminal in question,
        displaying characters as they are output.  This, obviously, is
        not something that should be attempted by anyone who does not
        have experience working with the Unix kernel.  Furthermore,
        whatever method you come up with will probably be quite
        non-portable.

      * If you want to do this to a particular hard-wired terminal all
        the time (e.g. if you want operators to be able to check the
        console terminal of a machine from other machines), you can
        actually splice a monitor into the cable for the terminal.  For
        example, plug the monitor output into another machine's serial
        port, and run a program on that port that stores its input
        somewhere and then transmits it out *another* port, this one
        really going to the physical terminal.  If you do this, you have
        to make sure that any output from the terminal is transmitted
        back over the wire, although if you splice only into the
        computer->terminal wires, this isn't much of a problem.  This is
        not something that should be attempted by anyone who is not very
        familiar with terminal wiring and such.

-- 
Ted Timar - tmatimar@empress.com
Empress Software, 3100 Steeles Ave E, Markham, Ont., Canada L3R 8T3

-----------------------------

From: Ted M A Timar <tmatimar@empress.com>
Subject: Frequently Asked Questions about Unix (3/7) [Biweekly posting]
Date: 20 Nov 92 06:00:51 GMT
Expires: 18 Dec 1992 06:00:22 GMT
Followup-To: comp.unix.questions
Supersedes: <unix-faq/part3_721029617@athena.mit.edu>
NNTP-Posting-Host: pit-manager.mit.edu
X-Last-Updated: 1992/10/21
To:       info-unix@sem.brl.mil

Archive-name: unix-faq/part3
Version: $Id: part3,v 2.0 92/10/20 12:07:07 tmatimar Exp $

These seven articles contain the answers to some Frequently Asked
Questions often seen in comp.unix.questions and comp.unix.shell.
Please don't ask these questions again, they've been answered plenty
of times already - and please don't flame someone just because they may
not have read this particular posting.  Thank you.

These articles are divided approximately as follows:

      1.*) General questions.
      2.*) Relatively basic questions, likely to be asked by beginners.
      3.*) Intermediate questions.
      4.*) Advanced questions, likely to be asked by people who thought
	   they already knew all of the answers.
      5.*) Questions pertaining to the various shells, and the differences.
      6.*) An overview of Unix variants.
      7.*) An comparison of configuration management systems (RCS, SCCS).

This article includes answers to:

      3.1)  How do I find out the creation time of a file?
      3.2)  How do I use "rsh" without having the rsh hang around
              until the remote command has completed?
      3.3)  How do I truncate a file?
      3.4)  Why doesn't find's "{}" symbol do what I want?
      3.5)  How do I set the permissions on a symbolic link?
      3.6)  How do I "undelete" a file?
      3.7)  How can a process detect if it's running in the background?
      3.8)  Why doesn't redirecting a loop work as intended?  (Bourne shell)
      3.9)  How do I run 'passwd', 'ftp', 'telnet', 'tip' and other interactive
              programs from a shell script or in the background?
      3.10) How do I find out the process ID of a program with a particular
            name from inside a shell script or C program?
      3.11) How do I check the exit status of a remote command
            executed via "rsh" ?
      3.12) Is it possible to pass shell variable settings into an awk program?
      3.13) How do I get rid of zombie processes that persevere?
      3.14) How do I get lines from a pipe as they are written instead of
            only in larger blocks.

If you're looking for the answer to, say, question 3.5, and want to skip
everything else, you can search ahead for the regular expression "^3.5)".

While these are all legitimate questions, they seem to crop up in
comp.unix.questions or comp.unix.shell on an annual basis, usually
followed by plenty of replies (only some of which are correct) and then
a period of griping about how the same questions keep coming up.  You
may also like to read the monthly article "Answers to Frequently Asked
Questions" in the newsgroup "news.announce.newusers", which will tell
you what "UNIX" stands for.

With the variety of Unix systems in the world, it's hard to guarantee
that these answers will work everywhere.  Read your local manual pages
before trying anything suggested here.  If you have suggestions or
corrections for any of these answers, please send them to to
tmatimar@empress.com.

3.1)  How do I find out the creation time of a file?

      You can't - it isn't stored anywhere.  Files have a last-modified
      time (shown by "ls -l"), a last-accessed time (shown by "ls -lu")
      and an inode change time (shown by "ls -lc"). The latter is often
      referred to as the "creation time" - even in some man pages -
      but that's wrong; it's also set by such operations as mv, ln,
      chmod, chown and chgrp.

      The man page for "stat(2)" discusses this.

3.2)  How do I use "rsh" without having the rsh hang around until the
      remote command has completed?

      (See note in question 2.7 about what "rsh" we're talking about.)

      The obvious answers fail:
      	    rsh machine command &
      or      rsh machine 'command &'

      For instance, try doing   rsh machine 'sleep 60 &' and you'll see
      that the 'rsh' won't exit right away.  It will wait 60 seconds
      until the remote 'sleep' command finishes, even though that
      command was started in the background on the remote machine.  So
      how do you get the 'rsh' to exit immediately after the 'sleep' is
      started?

      The solution - if you use csh on the remote machine:

	    rsh machine -n 'command >&/dev/null </dev/null &'

      If you use sh on the remote machine:

	    rsh machine -n 'command >/dev/null 2>&1 </dev/null &'

      Why?  "-n" attaches rsh's stdin to /dev/null so you could run the
      complete rsh command in the background on the LOCAL machine.
      Thus "-n" is equivalent to another specific "< /dev/null".
      Furthermore, the input/output redirections on the REMOTE machine
      (inside the single quotes) ensure that rsh thinks the session can
      be terminated (there's no data flow any more.)

      Note: The file that you redirect to/from on the remote machine
      doesn't have to be /dev/null; any ordinary file will do.

      In many cases, various parts of these complicated commands
      aren't necessary.

3.3)  How do I truncate a file?

      The BSD function ftruncate() sets the length of a file.  Xenix -
      and therefore SysV r3.2 and later - has the chsize() system
      call.  For other systems, the only kind of truncation you can do
      is truncation to length zero with creat() or open(..., O_TRUNC).

3.4)  Why doesn't find's "{}" symbol do what I want?

      "find" has a -exec option that will execute a particular command
      on all the selected files. Find will replace any "{}" it sees
      with the name of the file currently under consideration.

      So, some day you might try to use "find" to run a command on
      every file, one directory at a time.  You might try this:

	find /path -type d -exec command {}/\* \;

      hoping that find will execute, in turn

	command directory1/*
	command directory2/*
	...

      Unfortunately, find only expands the "{}" token when it appears
      by itself.  Find will leave anything else like "{}/*" alone, so
      instead of doing what you want, it will do

	command {}/*
	command {}/*
	...

      once for each directory.  This might be a bug, it might be a
      feature, but we're stuck with the current behaviour.

      So how do you get around this?  One way would be to write a
      trivial little shell script, let's say "./doit", that consists of

	command "$1"/*

      You could then use

	find /path -type d -exec ./doit {} \;

      Or if you want to avoid the "./doit" shell script, you can use

	find /path -type d -exec sh -c 'command $0/*' {} \;

      (This works because within the 'command' of "sh -c 'command' A B C ...",
       $0 expands to A, $1 to B, and so on.)

      or you can use the construct-a-command-with-sed trick

	find /path -type d -print | sed 's:.*:command &/*:' | sh

      If all you're trying to do is cut down on the number of times
      that "command" is executed, you should see if your system has the
      "xargs" command.  Xargs reads arguments one line at a time from
      the standard input and assembles as many of them as will fit into
      one command line.  You could use

	find /path -print | xargs command

      which would result in one or more executions of

	command file1 file2 file3 file4 dir1/file1 dir1/file2

      Unfortunately this is not a perfectly robust or secure solution.
      Xargs expects its input lines to be terminated with newlines, so
      it will be confused by files with odd characters such as newlines
      in their names.

3.5)  How do I set the permissions on a symbolic link?

      Permissions on a symbolic link don't really mean anything.  The
      only permissions that count are the permissions on the file that
      the link points to.

3.6)  How do I "undelete" a file?

      Someday, you are going to accidentally type something like
      "rm * .foo", and find you just deleted "*" instead of "*.foo".
      Consider it a rite of passage.

      Of course, any decent systems administrator should be doing
      regular backups.  Check with your sysadmin to see if a recent
      backup copy of your file is available.  But if it isn't, read
      on.

      For all intents and purposes, when you delete a file with "rm" it
      is gone.  Once you "rm" a file, the system totally forgets which
      blocks scattered around the disk comprised your file.  Even
      worse, the blocks from the file you just deleted are going to be
      the first ones taken and scribbled upon when the system needs
      more disk space.  However, never say never.  It is theoretically
      possible *if* you shut down the system immediately after the "rm"
      to recover portions of the data.  However, you had better have a
      very wizardly type person at hand with hours or days to spare to
      get it all back.

      Your first reaction when you "rm" a file by mistake is why not
      make a shell alias or procedure which changes "rm" to move files
      into a trash bin rather than delete them?  That way you can
      recover them if you make a mistake, and periodically clean out
      your trash bin.  Two points:  first, this is generally accepted
      as a *bad* idea.  You will become dependent upon this behaviour
      of "rm", and you will find yourself someday on a normal system
      where "rm" is really "rm", and you will get yourself in trouble.
      Second, you will eventually find that the hassle of dealing with
      the disk space and time involved in maintaining the trash bin, it
      might be easier just to be a bit more careful with "rm".  For
      starters, you should look up the "-i" option to "rm" in your
      manual.

      If you are still undaunted, then here is a possible simple
      answer.  You can create yourself a "can" command which moves
      files into a trashcan directory. In csh(1) you can place the
      following commands in the ".login" file in your home directory:

	alias can	'mv \!* ~/.trashcan'	   # junk file(s) to trashcan
	alias mtcan	'rm -f ~/.trashcan/*'	   # irretrievably empty trash
	if ( ! -d ~/.trashcan ) mkdir ~/.trashcan  # ensure trashcan exists

      You might also want to put a:

	rm -f ~/.trashcan/*

      in the ".logout" file in your home directory to automatically
      empty the trash when you log out.  (sh and ksh versions are left
      as an exercise for the reader.)

      MIT's Project Athena has produced a comprehensive
      delete/undelete/expunge/purge package, which can serve as a
      complete replacement for rm which allows file recovery.  This
      package was posted to comp.sources.misc (volume 17, issue
      023-026)

3.7)  How can a process detect if it's running in the background?

      First of all: do you want to know if you're running in the
      background, or if you're running interactively? If you're
      deciding whether or not you should print prompts and the like,
      that's probably a better criterion. Check if standard input
      is a terminal:

	    sh: if [ -t 0 ]; then ... fi
	    C: if(isatty(0)) { ... }

      In general, you can't tell if you're running in the background.
      The fundamental problem is that different shells and different
      versions of UNIX have different notions of what "foreground" and
      "background" mean - and on the most common type of system with a
      better-defined notion of what they mean, programs can be moved
      arbitrarily between foreground and background!

      UNIX systems without job control typically put a process into the
      background by ignoring SIGINT and SIGQUIT and redirecting the
      standard input to "/dev/null"; this is done by the shell.

      Shells that support job control, on UNIX systems that support job
      control, put a process into the background by giving it a process
      group ID different from the process group to which the terminal
      belongs.  They move it back into the foreground by setting the
      terminal's process group ID to that of the process.  Shells that
      do *not* support job control, on UNIX systems that support job
      control, typically do what shells do on systems that don't
      support job control.

3.8)  Why doesn't redirecting a loop work as intended?  (Bourne shell)

      Take the following example:

	foo=bar

	while read line
	do
		# do something with $line
		foo=bletch
	done < /etc/passwd

	echo "foo is now: $foo"

      Despite the assignment ``foo=bletch'' this will print
      ``foo is now: bar'' in many implementations of the Bourne shell.
      Why?  Because of the following, often undocumented, feature of
      historic Bourne shells: redirecting a control structure (such as
      a loop, or an ``if'' statement) causes a subshell to be created,
      in which the structure is executed; variables set in that
      subshell (like the ``foo=bletch'' assignment) don't affect the
      current shell, of course.

      The POSIX 1003.2 Shell and Tools Interface standardization
      committee forbids the behaviour described above, i.e. in P1003.2
      conformant Bourne shells the example will print ``foo is now:
      bletch''.

      In historic (and P1003.2 conformant) implementations you can use
      the following `trick' to get around the redirection problem:

	foo=bar

	# make file descriptor 9 a duplicate of file descriptor 0 (stdin);
	# then connect stdin to /etc/passwd; the original stdin is now
	# `remembered' in file descriptor 9; see dup(2) and sh(1)
	exec 9<&0 < /etc/passwd

	while read line
	do
		# do something with $line
		foo=bletch
	done

	# make stdin a duplicate of file descriptor 9, i.e. reconnect
	# it to the original stdin; then close file descriptor 9
	exec 0<&9 9<&-

	echo "foo is now: $foo"

      This should always print ``foo is now: bletch''.
      Right, take the next example:

	foo=bar

	echo bletch | read foo

	echo "foo is now: $foo"

      This will print ``foo is now: bar'' in many implementations,
      ``foo is now: bletch'' in some others.  Why?  Generally each part
      of a pipeline is run in a different subshell; in some
      implementations though, the last command in the pipeline is made
      an exception: if it is a builtin command like ``read'', the
      current shell will execute it, else another subshell is created.

      POSIX 1003.2 allows both behaviours so portable scripts cannot
      depend on any of them.

3.9)  How do I run 'passwd', 'ftp', 'telnet', 'tip' and other interactive
      programs from a shell script or in the background?

      These programs expect a terminal interface.  Shells makes no
      special provisions to provide one.  Hence, such programs cannot
      be automated in shell scripts.

      The 'expect' program provides a programmable terminal interface
      for automating interaction with such programs.  The following
      expect script is an example of a non-interactive version of
      passwd(1).

	# username is passed as 1st arg, password as 2nd
	set password [index $argv 2]
	spawn passwd [index $argv 1]
	expect "*password:"
	send "$password\r"
	expect "*password:"
	send "$password\r"
	expect eof

      expect can partially automate interaction which is especially
      useful for telnet, rlogin, debuggers or other programs that have
      no built-in command language.  The distribution provides an
      example script to rerun rogue until a good starting configuration
      appears.  Then, control is given back to the user to enjoy the game.

      Fortunately some programs have been written to manage the
      connection to a pseudo-tty so that you can run these sorts of
      programs in a script.

      To get expect, email "send pub/expect/expect.shar.Z" to
      library@cme.nist.gov or anonymous ftp same from
      durer.cme.nist.gov.

      Another solution is provided by the pty 4.0 program, which runs a
      program under a pseudo-tty session and was posted to
      comp.sources.unix, volume 25.  A pty-based solution using named
      pipes to do the same as the above might look like this:

	#!/bin/sh
	/etc/mknod out.$$ p; exec 2>&1
	( exec 4<out.$$; rm -f out.$$
	<&4 waitfor 'password:'
	    echo "$2"
	<&4 waitfor 'password:'
	    echo "$2"
	<&4 cat >/dev/null
	) | ( pty passwd "$1" >out.$$ )

      Here, 'waitfor' is a simple C program that searches for
      its argument in the input, character by character.

      A simpler pty solution (which has the drawback of not
      synchronizing properly with the passwd program) is

	#!/bin/sh
	( sleep 5; echo "$2"; sleep 5; echo "$2") | pty passwd "$1"

3.10) How do I find out the process ID of a program with a particular
      name from inside a shell script or C program?

      In a shell script:

      There is no utility specifically designed to map between program
      names and process IDs.  Furthermore, such mappings are often
      unreliable, since it's possible for more than one process to have
      the same name, and since it's possible for a process to change
      its name once it starts running.  However, a pipeline like this
      can often be used to get a list of processes (owned by you) with
      a particular name:

	    ps ux | awk '/name/ && !/awk/ {print $2}'

      You replace "name" with the name of the process for which you are
      searching.

      The general idea is to parse the output of ps, using awk or grep
      or other utilities, to search for the lines with the specified
      name on them, and print the PID's for those lines.  Note that the
      "!/awk/" above prevents the awk process for being listed.

      You may have to change the arguments to ps, depending on what
      kind of Unix you are using.

      In a C program:

      Just as there is no utility specifically designed to map between
      program names and process IDs, there are no (portable) C library
      functions to do it either.

      However, some vendors provide functions for reading Kernel
      memory; for example, Sun provides the "kvm_" functions, and Data
      General provides the "dg_" functions.  It may be possible for any
      user to use these, or they may only be useable by the super-user
      (or a user in group "kmem") if read-access to kernel memory on
      your system is restricted.  Furthermore, these functions are
      often not documented or documented badly, and might change from
      release to release.

      Some vendors provide a "/proc" filesystem, which appears as a
      directory with a bunch of filenames in it.  Each filename is a
      number, corresponding to a process ID, and you can open the file
      and read it to get information about the process.  Once again,
      access to this may be restricted, and the interface to it may
      change from system to system.

      If you can't use vendor-specific library functions, and you
      don't have /proc, and you still want to do this completely
      in C, you
      are going to have to do the grovelling through kernel memory
      yourself.  For a good example of how to do this on many systems,
      see the sources to "ofiles", available in the comp.sources.unix
      archives.  (A package named "kstuff" to help with kernel
      grovelling was posted to alt.sources in May 1991 and is also
      available via anonymous ftp as
      usenet/alt.sources/articles/{329{6,7,8,9},330{0,1}}.Z from
      wuarchive.wustl.edu.)

3.11) How do I check the exit status of a remote command
      executed via "rsh" ?

      This doesn't work:

	rsh some-machine some-crummy-command || echo "Command failed"

      The exit status of 'rsh' is 0 (success) if the rsh program
      itself completed successfully, which probably isn't what
      you wanted.

      If you want to check on the exit status of the remote program,
      you can try using Maarten Litmaath's 'ersh' script, which was
      posted to alt.sources in January, 1991.  ersh is a shell script
      that calls rsh, arranges for the remote machine to echo the
      status of the command after it completes, and exits with that
      status.

3.12) Is it possible to pass shell variable settings into an awk program?

      There are two different ways to do this.  The first involves
      simply expanding the variable where it is needed in the program.
      For example, to get a list of all ttys you're using:

	who | awk '/^'"$USER"'/ { print $2 }'				(1)

      Single quotes are usually used to enclose awk programs because
      the character '$' is often used in them, and '$' will be
      interpreted by the shell if enclosed inside double quotes, but
      not if enclosed inside single quotes.  In this case, we *want*
      the '$' in "$USER" to be interpreted by the shell, so we close
      the single quotes and then put the "$USER" inside double quotes.
      Note that there are no spaces in any of that, so the shell will
      see it all as one argument.  Note, further, that the double
      quotes probably aren't necessary in this particular case (i.e. we
      could have done

	who | awk '/^'$USER'/ { print $2 }'				(2)

      ), but they should be included nevertheless because they are
      necessary when the shell variable in question contains special
      characters or spaces.

      The second way to pass variable settings into awk is to use an
      often undocumented feature of awk which allows variable settings
      to be specified as "fake file names" on the command line.  For
      example:

	who | awk '$1 == user { print $2 }' user="$USER" -		(3)

      Variable settings take effect when they are encountered on the
      command line, so, for example, you could instruct awk on how to
      behave for different files using this technique.  For example:

	awk '{ program that depends on s }' s=1 file1 s=0 file2		(4)

      Note that some versions of awk will cause variable settings
      encountered before any real filenames to take effect before the
      BEGIN block is executed, but some won't so neither way should be
      relied upon.

      Note, further, that when you specify a variable setting, awk
      won't automatically read from stdin if no real files are
      specified, so you need to add a "-" argument to the end of your
      command, as I did at (3) above.

3.13) How do I get rid of zombie processes that persevere?

      From: jik@pit-manager.MIT.Edu (Jonathan I. Kamens)
      Date: Fri, 17 Jan 92 14:40:09 -0500

      Unfortunately, it's impossible to generalize how the death of
      child processes should behave, because the exact mechanism varies
      over the various flavors of Unix.

      First of all, by default, you have to do a wait() for child
      processes under ALL flavors of Unix.  That is, there is no flavor
      of Unix that I know of that will automatically flush child
      processes that exit, even if you don't do anything to tell it to
      do so.

      Second, under some SysV-derived systems, if you do
      "signal(SIGCHLD, SIG_IGN)" (well, actually, it may be SIGCLD
      instead of SIGCHLD, but most of the newer SysV systems have
      "#define SIGCHLD SIGCLD" in the header files), then child
      processes will be cleaned up automatically, with no further
      effort in your part.  The best way to find out if it works at
      your site is to try it, although if you are trying to write
      portable code, it's a bad idea to rely on this in any case.
      Unfortunately, POSIX doesn't allow you to do this; the behavior
      of setting the SIGCHLD to SIG_IGN under POSIX is undefined, so
      you can't do it if your program is supposed to be
      POSIX-compliant.

      If you can't use SIG_IGN to force automatic clean-up, then you've
      got to write a signal handler to do it.  It isn't easy at all to
      write a signal handler that does things right on all flavors of
      Unix, because of the following inconsistencies:

      On some flavors of Unix, the SIGCHLD signal handler is called if
      one *or more* children have died.  This means that if your signal
      handler only does one wait() call, then it won't clean up all of
      the children.  Fortunately, I believe that all Unix flavors for
      which this is the case have available to the programmer the
      wait3() call, which allows the WNOHANG option to check whether or
      not there are any children waiting to be cleaned up.  Therefore,
      on any system that has wait3(), your signal handler should call
      wait3() over and over again with the WNOHANG option until there
      are no children left to clean up.

      On SysV-derived systems, SIGCHLD signals are regenerated if there
      are child processes still waiting to be cleaned up after you exit
      the SIGCHLD signal handler.  Therefore, it's safe on most SysV
      systems to assume when the signal handler gets called that you
      only have to clean up one signal, and assume that the handler
      will get called again if there are more to clean up after it
      exits.

      On older systems, signal handlers are automatically reset to
      SIG_DFL when the signal handler gets called.  On such systems,
      you have to put "signal(SIGCHILD, catcher_func)" (where
      "catcher_func" is the name of the handler function) as the first
      thing in the signal handler, so that it gets reset.
      Unfortunately, there is a race condition which may cause you to
      get a SIGCHLD signal and have it ignored between the time your
      handler gets called and the time you reset the signal.
      Fortunately, newer implementations of signal() don't reset the
      handler to SIG_DFL when the handler function is called.  To get
      around this problem, on systems that do not have wait3() but do
      have SIGCLD, you need to reset the signal handler with a call to
      signal() after doing at least one wait() within the handler, each
      time it is called.

      The summary of all this is that on systems that have wait3(), you
      should use that and your signal handler should loop, and on
      systems that don't, you should have one call to wait() per
      invocation of the signal handler.

      One more thing -- if you don't want to go through all of this
      trouble, there is a portable way to avoid this problem, although
      it is somewhat less efficient.  Your parent process should fork,
      and then wait right there and then for the child process to
      terminate.  The child process then forks again, giving you a
      child and a grandchild.  The child exits immediately (and hence
      the parent waiting for it notices its death and continues to
      work), and the grandchild does whatever the child was originally
      supposed to.  Since its parent died, it is inherited by init,
      which will do whatever waiting is needed.  This method is
      inefficient because it requires an extra fork, but is pretty much
      completely portable.

3.14) How do I get lines from a pipe as they are written instead of only in
      larger blocks.

      From: jik@pit-manager.MIT.Edu (Jonathan I. Kamens)
      Date: Sun, 16 Feb 92 20:59:28 -0500

      The stdio library does buffering differently depending on whether
      it thinks it's running on a tty.  If it thinks it's on a tty, it
      does buffering on a per-line basis; if not, it uses a larger
      buffer than one line.

      If you have the source code to the client whose buffering you
      want to disable, you can use setbuf() or setvbuf() to change the
      buffering.

      If not, the best you can do is try to convince the program that
      it's running on a tty by running it under a pty, e.g. by using
      the "pty" program mentioned in question 3.9.

-- 
Ted Timar - tmatimar@empress.com
Empress Software, 3100 Steeles Ave E, Markham, Ont., Canada L3R 8T3

-----------------------------

From: Ted M A Timar <tmatimar@empress.com>
Subject: Frequently Asked Questions about Unix (5/7) [Biweekly posting]
Date: 20 Nov 92 06:00:52 GMT
Expires: 18 Dec 1992 06:00:22 GMT
Followup-To: comp.unix.questions
Supersedes: <unix-faq/part5_721029617@athena.mit.edu>
NNTP-Posting-Host: pit-manager.mit.edu
X-Last-Updated: 1992/10/21
To:       info-unix@sem.brl.mil

Archive-name: unix-faq/part5
Version: $Id: part5,v 2.0 92/10/20 12:07:13 tmatimar Exp $

These seven articles contain the answers to some Frequently Asked
Questions often seen in comp.unix.questions and comp.unix.shell.
Please don't ask these questions again, they've been answered plenty
of times already - and please don't flame someone just because they may
not have read this particular posting.  Thank you.

These articles are divided approximately as follows:

      1.*) General questions.
      2.*) Relatively basic questions, likely to be asked by beginners.
      3.*) Intermediate questions.
      4.*) Advanced questions, likely to be asked by people who thought
	   they already knew all of the answers.
      5.*) Questions pertaining to the various shells, and the differences.
      6.*) An overview of Unix variants.
      7.*) An comparison of configuration management systems (RCS, SCCS).

This article includes answers to:

      5.1)  Can shells be classified into categories?
      5.2)  How do I "include" one shell script from within another
            shell script?
      5.3)  Do all shells have aliases?  Is there something else that
            can be used?
      5.4)  How are shell variables assigned?
      5.5)  How can I tell if I am running an interactive shell?
      5.6)  What "dot" files do the various shells use?
      5.7)  I would like to know more about the differences between the
            various shells.  Is this information available some place?

If you're looking for the answer to, say, question 5.5, and want to skip
everything else, you can search ahead for the regular expression "^5.5)".

While these are all legitimate questions, they seem to crop up in
comp.unix.questions or comp.unix.shell on an annual basis, usually
followed by plenty of replies (only some of which are correct) and then
a period of griping about how the same questions keep coming up.  You
may also like to read the monthly article "Answers to Frequently Asked
Questions" in the newsgroup "news.announce.newusers", which will tell
you what "UNIX" stands for.

With the variety of Unix systems in the world, it's hard to guarantee
that these answers will work everywhere.  Read your local manual pages
before trying anything suggested here.  If you have suggestions or
corrections for any of these answers, please send them to to
tmatimar@empress.com.

5.1)  Can shells be classified into categories?

      From: wicks@dcdmjw.fnal.gov (Matthew Wicks)
      Date: Wed, 7 Oct 92 14:28:18 -0500

      In general there are two main class of shells.  The first class
      are those shells derived from the Bourne shell which includes sh,
      ksh, bash, and zsh.  The second class are those shells derived
      from C shell and include csh and tcsh.  In addition there is rc
      which most people consider to be in a "class by itself" although
      some people might argue that rc belongs in the Bourne shell class.

      With the classification above, using care, it is possible to
      write scripts that will work for all the shells from the Bourne
      shell category, and write other scripts that will work for all of
      the shells from the C shell category.

5.2)  How do I "include" one shell script from within another shell script?

      From: wicks@dcdmjw.fnal.gov (Matthew Wicks)
      Date: Wed, 7 Oct 92 14:28:18 -0500

      All of the shells from the Bourne shell category (including rc)
      use the "." command.  All of the shells from the C shell category
      use "source".

5.3)  Do all shells have aliases?  Is there something else that can be used?

      From: wicks@dcdmjw.fnal.gov (Matthew Wicks)
      Date: Wed, 7 Oct 92 14:28:18 -0500

      All of the major shells other than sh have aliases, but they
      don't all work the same way.  For example, some don't except
      arguments.
      
      Although not strictly equivalent, shell functions (which exist in
      all shells from the Bourne shell category) have almost the same
      functionality of aliases.  Shell functions can do things that
      aliases can't do.
      
      Use unalias to remove aliases and unset to remove functions.

5.4)  How are shell variables assigned?

      From: wicks@dcdmjw.fnal.gov (Matthew Wicks)
      Date: Wed, 7 Oct 92 14:28:18 -0500

      The shells from the C shell category use "set variable=value" for
      variables local to the shell and "setenv variable value" for
      environment variables.  To get rid of variables in these shells
      use unset and unsetenv.  The shells from the Bourne shell
      category use "variable=value" and may require an "export
      VARIABLE_NAME" to place the variable into the environment.  To
      get rid of the variables use unset.

5.5)  How can I tell if I am running an interactive shell?

      From: wicks@dcdmjw.fnal.gov (Matthew Wicks)
      Date: Wed, 7 Oct 92 14:28:18 -0500

      In the Bourne shell category look for the variable $PROMPT.  In
      the C shell category, look for the variable $prompt.

5.6)  What "dot" files do the various shells use?

      From: wicks@dcdmjw.fnal.gov (Matthew Wicks)
      Date: Wed, 7 Oct 92 14:28:18 -0500

      Although this may not be a complete listing, this provides the
      majority of information.

      csh
	  Some versions have system-wide .cshrc and .login files.  Every
	  version puts them in different places.

	  Start-up (in this order):
	      .cshrc   - always.
	      .login   - login shells.

	  Upon termination:
              .logout  - login shells.

	  Others:
	      .history - saves the history (based on $savehist).

      tcsh
	  Start-up (in this order):
	      /etc/csh.cshrc - always.
	      /etc/csh.login - login shells.
	      .tcshrc        - always.
	      .cshrc         - if no .tcshrc was present.
	      .login         - login shells

	  Upon termination:
              .logout        - login shells.

	  Others:
	      .history       - saves the history (based on $savehist).
	      .cshdirs       - saves the directory stack.

      sh
	  Start-up (in this order):
	      /etc/profile - login shells.
	      .profile     - login shells.

	  Upon termination:
	      any command (or script) specified using the command:
		 trap "command" 0

      ksh
	  Start-up (in this order):
	      /etc/profile - login shells.
	      .profile     - login shells.
	      $ENV         - always, if it is set.

	  Upon termination:
	      any command (or script) specified using the command:
		 trap "command" 0

      bash
	  Start-up (in this order):
              /etc/profile  - login shells.
              .bash_profile - login shells.
              .bashrc       - interactive shells.

	  Others:
              .inputrc      - Readline initialization.

      zsh
	  Start-up (in this order):
              .zshenv   - always, unless -f is specified.
              .zprofile - login shells.
              .zshrc    - interactive shells, unless -f is specified.
              .zlogin   - login shells.

	  Upon termination:
              .zlogout  - login shells.

      rc
	  Start-up:
              .rcrc - login shells

5.7)  I would like to know more about the differences between the
      various shells.  Is this information available some place?

      From: wicks@dcdmjw.fnal.gov (Matthew Wicks)
      Date: Wed, 7 Oct 92 14:28:18 -0500

      A very detailed comparison of sh, csh, tcsh, ksh, bash, zsh, and
      rc is available via anon.  ftp in several places:

      cs.uwp.edu (131.210.1.4):pub/vi/shell-100.BetaA.Z
      alf.uib.no (129.177.30.3):pub/lpf/misc/shell-100.BetaA.Z
      utsun.s.u-tokyo.ac.jp (133.11.11.11):misc/vi/shell-100.BetaA.Z

      This file compares the flags, the programming syntax,
      input/output redirection, and parameters/shell environment
      variables.  It doesn't discuss what dot files are used and the
      inheritance for environment variables and functions.

-- 
Ted Timar - tmatimar@empress.com
Empress Software, 3100 Steeles Ave E, Markham, Ont., Canada L3R 8T3

-----------------------------

From: Ted M A Timar <tmatimar@empress.com>
Subject: Frequently Asked Questions about Unix (7/7) [Biweekly posting]
Date: 20 Nov 92 06:00:54 GMT
Expires: 18 Dec 1992 06:00:22 GMT
Followup-To: comp.unix.questions
Supersedes: <unix-faq/part7_721029617@athena.mit.edu>
NNTP-Posting-Host: pit-manager.mit.edu
X-Last-Updated: 1992/10/21
To:       info-unix@sem.brl.mil

Archive-name: unix-faq/part7
Version: $Id: part7,v 2.0 92/10/20 12:07:46 tmatimar Exp $

These seven articles contain the answers to some Frequently Asked
Questions often seen in comp.unix.questions and comp.unix.shell.
Please don't ask these questions again, they've been answered plenty
of times already - and please don't flame someone just because they may
not have read this particular posting.  Thank you.

These articles are divided approximately as follows:

      1.*) General questions.
      2.*) Relatively basic questions, likely to be asked by beginners.
      3.*) Intermediate questions.
      4.*) Advanced questions, likely to be asked by people who thought
	   they already knew all of the answers.
      5.*) Questions pertaining to the various shells, and the differences.
      6.*) An overview of Unix variants.
      7.*) An comparison of configuration management systems (RCS, SCCS).

This article includes answers to:

      7.1)  RCS vs SCCS:  Introduction
      7.2)  RCS vs SCCS:  How do the interfaces compare?
      7.3)  RCS vs SCCS:  What's in a Revision File?
      7.4)  RCS vs SCCS:  What are the keywords?
      7.5)  What's an RCS symbolic name?
      7.6)  RCS vs SCCS:  How do they compare for performance?
      7.7)  RCS vs SCCS:  Version Identification.
      7.8)  RCS vs SCCS:  How do they handle with problems?
      7.9)  RCS vs SCCS:  Conversion.
      7.10) RCS vs SCCS:  Support
      7.11) RCS vs SCCS:  Command Comparison
      7.12) RCS vs SCCS:  Acknowledgements
      7.13) Can I get more information on configuration management systems?

If you're looking for the answer to, say, question 7.5, and want to skip
everything else, you can search ahead for the regular expression "^7.5)".

While these are all legitimate questions, they seem to crop up in
comp.unix.questions or comp.unix.shell on an annual basis, usually
followed by plenty of replies (only some of which are correct) and then
a period of griping about how the same questions keep coming up.  You
may also like to read the monthly article "Answers to Frequently Asked
Questions" in the newsgroup "news.announce.newusers", which will tell
you what "UNIX" stands for.

With the variety of Unix systems in the world, it's hard to guarantee
that these answers will work everywhere.  Read your local manual pages
before trying anything suggested here.  If you have suggestions or
corrections for any of these answers, please send them to to
tmatimar@empress.com.

7.1)  RCS vs SCCS:  Introduction

      Date: Sat, 10 Oct 92 19:34:39 +0200
      From: Bill Wohler <wohler@sap-ag.de>

      The majority of the replies (in a recent poll) were in favor of
      RCS, a few for SCCS, and a few suggested alternatives such as CVS.

      Functionally RCS and SCCS are practically equal, with RCS having
      a bit more features since it continues to be updated.

      Note that RCS learned from the mistakes of SCCS...

7.2)  RCS vs SCCS:  How do the interfaces compare?

      Date: Sat, 10 Oct 92 19:34:39 +0200
      From: Bill Wohler <wohler@sap-ag.de>

      RCS has an easier interface for first time users.  There are less
      commands, it is more intuitive and consistent, and it provides
      more useful arguments.

      Branches have to be specifically created in SCCS.  In RCS, they
      are checked in as any other version.

7.3)  RCS vs SCCS:  What's in a Revision File?

      Date: Sat, 10 Oct 92 19:34:39 +0200
      From: Bill Wohler <wohler@sap-ag.de>

      RCS keeps history in files with a ",v" suffix.  SCCS keeps
      history in files with a "s." prefix.

      RCS looks for RCS files automatically in the current directory or
      in a RCS subdirectory, or you can specify an alternate RCS file.
      The sccs front end to SCCS always uses the SCCS directory.  If
      you don't use the sccs front end, you must specify the full SCCS
      filename.

      RCS stores its revisions by holding a copy of the latest version
      and storing backward deltas.  SCCS uses a "merged delta"
      concept.

      All RCS activity takes place within a single RCS file.  SCCS
      maintains several files.  This can be messy and confusing.

      Editing either RCS or SCCS files is a bad idea because mistakes
      are so easy to make and so fatal to the history of the file.
      Revision information is easy to edit in both types, whereas one
      would not want to edit the actual text of a version in RCS.  If
      you edit an SCCS file, you will have to recalculate the checksum
      using the admin program.

7.4)  RCS vs SCCS:  What are the keywords?

      Date: Sat, 10 Oct 92 19:34:39 +0200
      From: Bill Wohler <wohler@sap-ag.de>

      RCS and SCCS use different keywords that are expanded in the
      text.  For SCCS the keyword "%I%" is replaced with the revision
      number if the file is checked out for reading.

      The RCS keywords are easier to remember, but keyword expansion is
      more easily customized in SCCS.

      In SCCS, keywords are expanded on a read-only get.  If a version
      with expanded keywords is copied into a file that will be
      deltaed, the keywords will be lost and the version information in
      the file will not be updated.  On the other hand, RCS retains the
      keywords when they are expanded so this is avoided.

7.5)  What's an RCS symbolic name?

      Date: Sat, 10 Oct 92 19:34:39 +0200
      From: Bill Wohler <wohler@sap-ag.de>

      RCS allows you treat a set of files as a family of files while
      SCCS is meant primarily for keeping the revision history of
      files.

      RCS accomplishes that with symbolic names: you can mark all the
      source files associated with an application version with `rcs
      -n', and then easily retrieve them later as a cohesive unit.  In
      SCCS you would have to do this by writing a script to write or
      read all file names and versions to or from a file.

7.6)  RCS vs SCCS:  How do they compare for performance?

      Date: Sat, 10 Oct 92 19:34:39 +0200
      From: Bill Wohler <wohler@sap-ag.de>

      Since RCS stores the latest version in full, it is much faster in
      retrieving the latest version.  After RCS version 5.6, it is also
      faster than SCCS in retrieving older versions.

7.7)  RCS vs SCCS:  Version Identification.

      Date: Sat, 10 Oct 92 19:34:39 +0200
      From: Bill Wohler <wohler@sap-ag.de>

      SCCS is able to determine when a specific line of code was added
      to a system.

7.8)  RCS vs SCCS:  How do they handle with problems?

      Date: Sat, 10 Oct 92 19:34:39 +0200
      From: Bill Wohler <wohler@sap-ag.de>

      If you are missing the sccs or rcs tools, or the RCS or SCCS file
      is corrupt and the tools don't work on it, you can still retrieve
      the latest version in RCS.  Not true with SCCS.

7.9)  RCS vs SCCS:  Conversion.

      Date: Sat, 10 Oct 92 19:34:39 +0200
      From: Bill Wohler <wohler@sap-ag.de>

      RCS provides a program to convert from SCCS to RCS.  One would
      have to write his own program to convert from RCS to SCCS.

7.10) RCS vs SCCS:  Support

      Date: Sat, 10 Oct 92 19:34:39 +0200
      From: Bill Wohler <wohler@sap-ag.de>

      SCCS is supported by AT&T.  RCS is supported by the Free Software
      Foundation.  Therefore RCS runs on many more platforms, including
      PCs.

      Most make programs recognize SCCS's "s."  prefix while GNU make
      is one of the few that handles RCS's ",v" suffix.

      Some tar programs have a -F option that ignores either RCS
      directories, or SCCS directories or both.

7.11) RCS vs SCCS:  Command Comparison

      Date: Sat, 10 Oct 92 19:34:39 +0200
      From: Bill Wohler <wohler@sap-ag.de>

      SCCS                        RCS                   Explanation
      ====                        ===                   ===========

      sccs admin -i -nfile file   ci file               Checks in the file
                                                        for the first time,
                                                        creating the revision
                                                        history file.

      sccs get file               co file               Check out a file for
                                                        reading.

      sccs edit file              co -l file            Check out a file for
                                                        modification.

      sccs delta file             ci file               Check in a file
                                                        previously locked.

      what file                   ident file            Print keyword
                                                        information.

      sccs prs file               rlog file             Print a history of
                                                        the file.

      sccs sccsdiff -rx -ry file  rcsdiff -rx -ry file  Compare two
                                                        revisions.

      sccs diffs file             rcsdiff file          Compare current with
                                                        last revision.

      sccs edit -ix-y file        rcsmerge -rx-y file   Merge changes between
                                                        two versions into
                                                        file.

      ???                         rcs -l file           Lock the latest
                                                        revision.

      ???                         rcs -u file           Unlock the latest
                                                        revision.  Possible
                                                        to break another's 
                                                        lock, but mail is
                                                        sent to the other
                                                        user explaining why.

7.12) RCS vs SCCS:  Acknowledgements

      Date: Sat, 10 Oct 92 19:34:39 +0200
      From: Bill Wohler <wohler@sap-ag.de>

      I would like to thank the following persons for contributing to
      these articles.  I'd like to add your name to the list--please
      send comments or more references to Bill Wohler <wohler@sap-ag.de>.

	Karl Vogel <vogel@c-17igp.wpafb.af.mil>
	Mark Runyan <runyan@hpcuhc.cup.hp.com>
	Paul Eggert <eggert@twinsun.com>
	Greg Henderson <henders@infonode.ingr.com>
	Dave Goldberg <dsg@mbunix.mitre.org>
	Rob Kurver <rob@pact.nl>
	Raymond Chen <rjc@math.princeton.edu>
	Dwight <dwight@s1.gov>

7.13) Can I get more information on configuration management systems?

      Date: Thu Oct 15 10:27:47 EDT 1992
      From: Ted Timar <tmatimar@empress.com>

      Bill Wohler, who compiled all of the information in this part of
      the FAQ, has compiled much more information.  This information is
      available for ftp from ftp.wg.omron.co.jp (133.210.4.4) under
      "pub/unix-faq/docs/rev-ctl-sys".

-----------------------------

From: Ted M A Timar <tmatimar@empress.com>
Subject: Frequently Asked Questions about Unix (6/7) [Biweekly posting]
Date: 20 Nov 92 06:00:56 GMT
Expires: 18 Dec 1992 06:00:22 GMT
Followup-To: comp.unix.questions
Supersedes: <unix-faq/part6_721029617@athena.mit.edu>
NNTP-Posting-Host: pit-manager.mit.edu
X-Last-Updated: 1992/10/21
To:       info-unix@sem.brl.mil

Archive-name: unix-faq/part6
Version: $Id: part6,v 2.0 92/10/20 12:07:30 tmatimar Exp $

These seven articles contain the answers to some Frequently Asked
Questions often seen in comp.unix.questions and comp.unix.shell.
Please don't ask these questions again, they've been answered plenty
of times already - and please don't flame someone just because they may
not have read this particular posting.  Thank you.

These articles are divided approximately as follows:

      1.*) General questions.
      2.*) Relatively basic questions, likely to be asked by beginners.
      3.*) Intermediate questions.
      4.*) Advanced questions, likely to be asked by people who thought
	   they already knew all of the answers.
      5.*) Questions pertaining to the various shells, and the differences.
      6.*) An overview of Unix variants.
      7.*) An comparison of configuration management systems (RCS, SCCS).

This article includes answers to:

      6.1)  Disclaimer and introduction.
      6.2)  A very brief look at Unix history.
      6.3)  Main Unix flavors.
      6.4)  Unix Standards.
      6.5)  Identifying your Unix flavor.
      6.6)  Brief notes on some well-known (commercial/PD) Unices.
      6.7)  Real-time Unices.
      6.8)  Unix glossary.
      6.9)  Acknowledgements.

If you're looking for the answer to, say, question 6.5, and want to skip
everything else, you can search ahead for the regular expression "^6.5)".

While these are all legitimate questions, they seem to crop up in
comp.unix.questions or comp.unix.shell on an annual basis, usually
followed by plenty of replies (only some of which are correct) and then
a period of griping about how the same questions keep coming up.  You
may also like to read the monthly article "Answers to Frequently Asked
Questions" in the newsgroup "news.announce.newusers", which will tell
you what "UNIX" stands for.

With the variety of Unix systems in the world, it's hard to guarantee
that these answers will work everywhere.  Read your local manual pages
before trying anything suggested here.  If you have suggestions or
corrections for any of these answers, please send them to to
tmatimar@empress.com.

6.1)  Disclaimer and introduction.

      From: "Pierre (P.) Lewis" <lew@bnr.ca>
      Date: Sun, 11 Oct 1992 15:29:00 +0000
      Version: 2.0

      The following is offered with no guarantee as to accuracy or
      completeness.  I have done what I can in the time available and
      it still is very much work in progress.  I hope to keep improving
      this summary.  Comments welcome:  lew@bnr.ca.  Acknowledgements
      at the end.

      First a short definition.  By Unix we mean an operating system
      typically written in C, with a hierarchical file system,
      integration of file and device I/O, whose system call interface
      includes services such as fork(), pipe(), and whose user
      interface includes tools such as cc, troff, grep, awk, and a
      choice of shell.  Note that UNIX is a registered trademark of USL
      (AT&T), but will be used here in its generic sense.

      Most Unices (the more common plural form) are derived more or
      less directly from AT&T code (some code from the first C version
      is presumably still left in most), but there are also clones
      (i.e. Unix-compatible systems with no AT&T code).

      In addition, there are also Unix-like environments (e.g. VOS)
      sitting on top of other OSs, and OSs inspired from Unix (yes,
      even DOS!).  These are not covered here.  Little on real-time
      Unices yet (although more is planned).

      Unix comes in an incredible variety of flavors.  This is to a
      large extent due to availability of sources and the ease of
      porting and modifying Unix.  Typically, a vendor of Unix will
      start with one basic flavor (see below), take ideas/code from the
      other major flavor, add and change many things, etc.  This
      results in yet another new Unix flavor.  Today, there are
      literally hundreds of Unices available, the closest thing to
      standard Unix being (by definition) System V.

      This answer was put together mostly from information on the net
      and email.  Some specific sources are also mentioned in the
      appropriate sections.

6.2)  A very brief look at Unix history.

      From: "Pierre (P.) Lewis" <lew@bnr.ca>
      Date: Sun, 11 Oct 1992 15:29:00 +0000
      Version: 2.0

      Unix history goes back to 1969 and the famous "little-used PDP-7
      in a corner" on which Ken Thompson, Dennis Ritchie (the R in K&R)
      and others started work on what was to become Unix.  The name
      "Unix" was intended as a pun on Multics (and was written "Unics"
      at first -- UNiplexed Information and Computing System).

      For the first 10 years, Unix development was essentially confined
      to Bell Labs.  These initial versions were labeled "Version n" or
      "Nth Edition" (of the manuals), and were for DEC's PDP-11 (16
      bits) and later VAXen (32 bits).  Some significant versions
      include:

      V1 (1971):  1st Unix version, in assembler on a PDP-11/20.
	 Included file system, fork(), roff, ed.  Was used as a text
	 processing tool for preparation of patents.  Pipe() appeared
	 first in V2!

      V4 (1973):  Rewritten in C, which is probably the most
	 significant event in this OS's history: it means Unix can be
	 ported to a new hardware in months, and changes are easy.  The
	 C language was originally designed for the Unix operating
	 system, and hence there is a strong synergy between C and Unix.

      V6 (1975):  First version of Unix widely available outside
	 Bell Labs (esp.  in universities).  This was also the start of
	 Unix diversity and popularity.  1.xBSD (PDP-11) was derived
	 from this version.  J. Lions published "A commentary on the
	 Unix Operating System" based on V6.

      V7 (1979):  For many, this is the "last true Unix", an
	 "improvement over all preceding and following Unices"
	 [Bourne].  It included full K&R C, uucp, Bourne shell.  V7 was
	 ported to the VAX as 32V.  The V7 kernel was a mere 40
	 Kbytes!

         Here (for reference) the system calls of V7:
	    _exit, access, acct, alarm, brk, chdir, chmod, chown,
	    chroot, close, creat, dup, dup2, exec*, exit, fork, fstat,
	    ftime, getegid, geteuid, getgid, getpid, getuid, gtty,
	    indir, ioctl, kill, link, lock, lseek, mknod, mount,
	    mpxcall, nice, open, pause, phys, pipe, pkoff, pkon,
	    profil, ptrace, read, sbrk, setgid, setuid, signal, stat,
	    stime, stty, sync, tell, time, times, umask, umount,
	    unlink, utime, wait, write.

      These Vn versions were developed by the Computer Research Group
      (CRG) of Bell Labs.  Another group, the Unix System Group (USG),
      was responsible for support.  A third group at Bell Labs was also
      involved in Unix development, the Programmer's WorkBench (PWB),
      to which we owe, for example, sccs, named pipes and other
      important ideas.  Both groups were merged into Unix System
      Development Lab in 1983.

      Work on Unix continued at Bell Labs in the 1980s.  The V series
      was further developed by the CRG (Stroustrup mentions V10 in the
      2nd edition of his book on C++), but we don't seem to hear much
      about this otherwise.  The company now responsible for Unix
      (System V) is called Unix System Laboratories (USL) and is
      majority-owned by AT&T.

      But much happened to Unix outside AT&T, especially at Berkeley
      (where the other major flavor comes from).  Vendors (esp. of
      workstations) also contributed much (e.g. Sun's NFS).

      The book "Life with Unix" by Don Libes and Sandy Ressler is
      fascinating reading for anyone interested in Unix, and covers a
      lot of the history, interactions, etc..  Much in the present
      section is summarized from this book.

6.3)  Main Unix flavors.

      From: "Pierre (P.) Lewis" <lew@bnr.ca>
      Date: Sun, 11 Oct 1992 15:29:00 +0000
      Version: 2.0

      Until recently, there were basically two main flavors of Unix:
      System V (five) from AT&T, and the Berkeley Software Distribution
      (BSD).  SVR4 is essentially a merge of these two flavors.  End
      '91, OSF/1 from the Open Software Foundation was released (as a
      direct competitor to System V) and may (future will tell) change
      this picture.

      The following lists the main releases and features of System V,
      BSD and OSF/1.

      System V from AT&T.  Typical of Intel hardware.  Most often
	 ported Unix, typically with BSD enhancements (csh, job
	 control, termcap, curses, vi, symbolic links).  System V
	 evolution is now overseen by Unix International (UI).  UI
	 members include AT&T, Sun, ....
	 Newsgroup: comp.unix.sysv[23]86.  Main releases:

         - System III (1982): first commercial Unix from AT&T
           - FIFOs (named pipes)  (later?)

         - System V (1983):
           - IPC package (shm, msg, sem)

         - SVR2 (1984):
           - shell functions (sh)
           - SVID (System V Interface Definition)

         - SVR3 (1986) for ? platforms:
           - STREAMS (inspired by V8), poll(), TLI (network software)
           - RFS
           - shared libs
           - SVID 2
           - demand paging (if hardware supports)

         - SVR3.2:
           - merge with Xenix (Intel 80386)
           - networking

         - SVR4 (1988), mainstream of Unix implementations, merge of
	   System V, BSD, and SunOS.
           - From SVR3: sysadmin, terminal I/F, printer (from BSD?),
	     RFS, STREAMS, uucp
           - From BSD: FFS, TCP/IP, sockets, select(), csh
           - From SunOS: NFS, OpenLook GUI, X11/NeWS, virtual memory
	     subsystem with memory-mapped files, shared libraries
	     (!= SVR3 ones?)
           - ksh
           - ANSI C
           - Internationalization (8-bit clean)
           - ABI (Application Binary Interface -- routines instead of traps)
           - POSIX, X/Open, SVID3

         - SVR4.1
           - async I/O (from SunOS?)

         - SVR4.2 (based on SVR4.1ES)
           - Veritas FS, ACLs
           - Dynamically loadable kernel modules

         - Future:
           - SVR4 MP (multiprocessor)
           - Use of Chorus microkernel?

      Berkeley Software Distribution (BSD).  Typical of VAXen, RISCs,
	 many workstations.  More dynamic, research versions now than
	 System V.  BSD is responsible for much of the popularity of
	 Unix.  Most enhancements to Unix started here.  The group
	 responsible at UCB (University of California at Berkeley) is
	 the Computer System Research Group (CSRG).  They closed down
	 in 1992.  Newsgroup: comp.unix.bsd.  Main releases:

         (much reorganized wrt dates and releases, hope it's converging)

         - 2.xBSD (1978) for PDP-11, still of significance? (2.11BSD
	   was released in 1992!).
           - csh

         - 3BSD (1978):
           - virtual memory

         - 4.?BSD:
           - termcap, curses
           - vi

         - 4.0BSD (1980):

         - 4.1BSD (?): base of later AT&T CRG versions
           - job control
           - automatic kernel config
           - vfork()

         - 4.2BSD (1983):
           - TCP/IP, sockets, ethernet
           - UFS: long file names, symbolic links
           - new reliable signals (4.1 reliable signals now in SVR3)
           - select()

         - 4.3BSD (1986) for VAX, ?:
         - 4.3 Tahoe (1988): 4.3BSD with sources, support for Tahoe
	   (32-bit supermini)
           - Fat FFS
           - New TCP algorithms
         - 4.3 Reno (1990) for VAX, Tahoe, HP 9000/300:
           - most of P1003.1
           - NFS (from Sun)
           - MFS (memory file system)
           - OSI: TP4, CLNP, ISODE's FTAM, VT and X.500;  SLIP
           - Kerberos

         - 4.4BSD (will we ever see it?) for HP 9000, Sparc, 386, DEC, Tahoe:
           - new FS organization, new process internals, new virtual
	     memory based on Mach 2.5
           - POSIX compatibility
           - OSI (based on ISODE), X.25

      The Open Software Foundation (OSF) released its Unix called OSF/1
	 end of 1991.  Still requires an SVR2 license.
	 Compatible/compliant with SVID 2 (and 3 coming), POSIX,
	 X/Open, etc..  OSF members include Apollo, Dec, HP, IBM, ....

         - OSF/1 (1991):
           - based on Mach 2.5 kernel
           - symmetric multiprocessing, parallelized kernel, threads
           - logical volumes, disk mirroring, UFS (native), S5 FS, NFS
           - enhanced security (B1 with some B2, B3; or C2), 4.3BSD admin
           - STREAMS, TLI/XTI, sockets
           - shared libs, dynamic loader (incl. kernel)
           - Motif GUI

         - Future:
           - OSF/1 MK (mikrokernel) based on Mach 3.0

      This list of major flavors should probably also include Xenix
      which has been the basis for many ports.  Derived from V7, S III
      and finally System V, it is similar externally but significantly
      changed internally (performance-tuned for micros).


      Two very good books describe the internals of the two main flavors.
      These are:
      - System V: "Design of the Unix Operating SYstem", M.J. Bach.
      - BSD: "Design and Implementation of the 4.3BSD Unix Operating System",
        Leffler, McKusick, Karels, Quaterman.
      For a good introduction to OSF/1 (not quite as technical as the
      previous two), see: "Guide to OSF/1, A Technical Synopsis",
      published by O'Reilly.  On SunOS, "Virtual Memory Architecture in
      SunOS" and "Shared Libraries in SunOS" in Summer 1989 USENIX
      Proceedings.

      A good set of articles on where Unix is going is "Unix Variants"
      in the Apr 92 issue of Unix Review.  Other good sources of
      information include the bsd-faq file, and many of the newsgroups
      mentioned in the text.

6.4)  Unix Standards.

      From: "Pierre (P.) Lewis" <lew@bnr.ca>
      Date: Sun, 11 Oct 1992 15:29:00 +0000
      Version: 2.0

      This section briefly describes the more important standards
      relevant to Unix.

      - IEEE:
        - 802.x (LAN) standards (LLC, ethernet, token ring, token bus)
        - POSIX (ISO 9945?): Portable Operating System I/F (Unix, VMS
	  and OS/2!) (only ? have been finalized at this point)
          - 1003.1:  library procedures (mostly system calls) -- roughly V7
                     except for signals and terminal I/F (1990)
          - 1003.2:  shell and utilities
          - 1003.3:  test methods and conformance
	  - 1003.4:  real-time: binary semaphores, process memory
		     locking, memory-mapped files, shared memory,
		     priority scheduling, real-time signals, clocks and
		     timers, IPC message passing, synchronized I/O,
		     asynchronous I/O, real-time files
          - 1003.5:  Ada language bindings
          - 1003.6:  security
          - 1003.7:  system admin (incl. printing)
          - 1003.8:  transparent file access
          - 1003.9:  FORTRAN language bindings
          - 1003.10: super computing
          - 1003.12: protocol-independent I/Fs
          - 1003.13: real-time profiles
          - 1003.15: supercomputing batch I/Fs
          - 1003.16: C-language bindings (?)
          - 1003.17: directory services
          - 1003.19: FORTRAN 90 language bindings

      - X/Open (consortium of vendors):
        - X/Open Portability Guides (XPGn):
          - XPG2 (1987), strong SV influence
            Vol 1:  commands and utilities
            Vol 2:  system calls and libraries
            Vol 3:  terminal I/F (curses, termio), IPC (SV),
		    internationalization
            Vol 4:  programming languages (C, COBOL!)
            Vol 5:  data management (ISAM, SQL)
          - XPG3 adds: ?
        - XOM series of interfaces:
          - XOM (X/Open Object Management) generic I/F mechanisms for
	    following
          - XDS (X/Open Directory Service)
          - XMH (X/Open Mail ??)
          - XCM (X/Open Consolidated Management) (not yet approved?)

      - AT&T
        - System V Interface Definition (SVID)
          - SVID1 (1985, SVR2)
            Vol 1:  system calls and libraries (similar to XPG2.1)
          - SVID2 (1986, SVR3)
            Vol 1:  system calls and libraries (base, kernel extensions)
            Vol 2:  commands and utilities (base, advanced, admin, software
                    development), terminal I/F
            Vol 3:  terminal I/F (again), STREAMS and TLI, RFS
          - SVID3 (19??, SVR4) adds
            Vol 4:  ??  &c
        - APIs
          - Transport Library Interface (TLI)
          - ACSE/Presentation Library Interface (APLI)

6.5)  Identifying your Unix flavor.

      From: "Pierre (P.) Lewis" <lew@bnr.ca>
      Date: Sun, 11 Oct 1992 15:29:00 +0000
      Version: 2.0

      This section lists a number of things you can look at in
      attempting to identify the base flavor of your Unix.  Given the
      significant exchange of code and ideas between the various
      flavors and the many changes made by vendors, any statement such
      as "this Unix is an SVR2" is at best a statistical statement
      (except for some SVRn ports).  Also many Unices offer most of
      both worlds (either mixed as in SunOS or strictly separated as in
      Apollo?).  So this section is perhaps not very useful...

      The list of features in previous sections can also help.  For
      example, if a system has a poll(2) but no select(2), it is highly
      probable that it is derived from SVR3.  Also the name of the OS
      can provide a clue, as well as the logon message (e.g.  SGI's
      "Irix SVR3.3.2") or the output of "uname -a" command.  Available
      commands can also provide hints but this is probably less
      reliable than kernel features.  For example, the type of terminal
      initialization (inittab or ttys) is a more reliable indicator
      than the print subsystem.

      Feature            Typical in SVRx          Typical in xBSD

      kernel name        /unix                    /vmunix
      terminal init      /etc/inittab             /etc/ttys (only getty to 4.3)
      boot init          /etc/rc.d directories    /etc/rc.* files
      mounted FSs        /etc/mnttab              /etc/mtab
      usual shell        sh, ksh                  csh, #! hack
      native FS          S5 (blk: 512-2K)         UFS (blk: 4K-8K)
                         file names <= 14 bytes   file names < 255 bytes
      groups             need newgrp(1)           automatic membership
                         SVR4: multiple groups
      print subsystem    lp, lpstat, cancel       lpr, lpq, lprm (lpd daemon) ??
      terminal control   termio, terminfo,        termios (sgtty before 4.3reno)
                         SVR4: termios (POSIX)    termcap
      job control        >= SVR4                  yes
      ps command         ps -ef                   ps -aux
      string fcns        memset, memcpy           bzero, bcopy
      process mapping    /proc  (SVR4)

6.6)  Brief notes on some well-known (commercial/PD) Unices.

      From: "Pierre (P.) Lewis" <lew@bnr.ca>
      Date: Sun, 11 Oct 1992 15:29:00 +0000
      Version: 2.0

      (I am not at all satisfied with this section, unfortunately I
      have neither the time nor the documents to make it much better
      (wrt contents).  Should only list Unices known by a reasonably
      wide audience.  Small and non-US Unices welcome, e.g. Eurix.  In
      need of reformatting)

      This section lists (in alphabetical order) some of the better
      known Unices along with a brief description of their nature.

      AIX:  IBM's Unix, based on SVR2 (later up to SVR3.2?) with varying
	 degrees of BSD extensions, for various hardwares.  Proprietary
	 system admin (SMIT).  Both 850 and Latin-1 CPs.  Quite
	 different from most Unices and among themselves.
	 Newsgroup: comp.unix.aix.
         - 1.x (for 386 PS/2)
         - 2.x (for PC RTs)
         - 3.x (for RS/6000), paging kernel, logical volume manager, i18n;
           3.2 adds TLI/STREAMS
         - there is also a version for S/370 mainframes (as task under VM)
         Was to have been base for OSF/1 until Mach was chosen instead.

      AOS (IBM):  4.3BSD port to IBM PC RT (for educational institutes).
         Don't confuse with DG's proprietary OS of same name.

      Arix:  SV

      A/UX (Apple): SV with Berkeley enhancements, NFS, Mac GUI.  System 6
         (later System 7) runs as guest of A/UX (opposite of MachTen).
	 Newsgroup: comp.unix.aux.
         - 2.0:  SVR2 with 4.2BSD, system 6 Mac applications.
         - 3.0 (1992): SVR2.2 with 4.3BSD, system 7 applications.

      BOS for Bull's DPX/2 (680x0)
         - V1 (1990): SVR3 with BSD extensions (FFS, select, sockets),
	   symmetric MP, X11R3
         - V2 (1991): adds job control, disk mirroring, C2 security,
	   DCE extensions

      386BSD: Jolitz's port of Net2 software.  Posix, 32-bit, still in alpha.

      BSD/386 (80386):  from BSDI, with source (augmented Net2 software)
         Newsgroup: comp.unix.bsd.

      Chorus/MiXV:  Unix SVR3.2 (SVR4) over Chorus nucleus, ABI/BCS.

      Coherent (80286):  Unix clone compatible with V7, some SVR2 (IPC).
         V4.0 is 32-bit.  Newsgroup: comp.os.coherent

      Consensys: SVR4

      CTIX: SV-based, from Convergent

      D-NIX:  SV

      DomainIX (Apollo):  dual Unix over Apollo Domain operating system

      DomainOS (Apollo):  BSD 4.2? with System V? (strict differentiation?)
         - 10.x

      DVIX (NT's DVS):  SVR2

      DYNIX (Sequent): 4.2BSD-based

      DYNIX/PTX: SVR3-based

      Esix (80386):  pure SVR4, X11, OpenLook (NeWS), Xview

      Eurix (80?86):  SVR3.2 (german?)

      FTX: Stratus fault-tolerant OS (68K or i860-i960 hardware)

      GNU Hurd (?):  vaporware from the Free Software Foundation (FSF):
	 Unix emulator over Mach 3.0 kernel.  Many GNU tools are very
	 popular (emacs) and used in the PD Unices.

      HP-UX (HP):  old from S III (SVRx), now SVR2 (4.2BSD?) with SV utilities
         (they have trouble making up their minds).
         - 6.5: SVR2
         - 7.0: SVR3.2, symlinks
         - 7.5
         - 8.0: BSD based? for HP-9000 CISC (300/400) and RISC (800/700)

      Interactive SVR3.2 (80x86): pure SVR3.  Interactive has been bought
         by Sun; will their system survive Solaris?

      Idris:  first Unix clone by Whitesmith.
         - 4D

      Irix (SGI):  SVR3.2, much BSD.  Newsgroup: comp.sys.sgi.

      Linux (80386):  PD Unix, SVish.  Available with sources.
         Newsgroup: comp.os.linux

      MachTen, Tenon Intersystems:  runs as a guest of System 6, no memory
         protection, 4.3BSD environment with TCP, NFS.

      MacMach (Mac II): 4.3BSD over Mach 3.0 microkernel, X11, Motif, GNU
         software, sources, experimental System 7 as Mach task.

      Mach386: from Mt Xinu.  Based on Mach 2.5, with 4.3BSD-Tahoe
         enhancements.  Also 2.6 MSD (Mach Source Distribution).

      Microport (80x86):  pure SVR4, X11, OpenLook GUI

      Minix (80x86, Atari, Amiga, Mac):  Unix clone compatible with V7.
         Sold with sources.  Being POSIXified (sp?).  Newsgroup: comp.os.minix.

      MipsOS:  SVish (RISC/OS, now dropped, was BSDish)

      more/BSD (VAX, HP 9000/300):  Mt Xinu's Unix, based on 4.3BSD-Tahoe.
         Newsgroup: comp.os.xinu?

      Net/2 tape (from Berkeley, 1991): BSD Unix, essentially compatible with
         4.3BSD, includes only sources free of AT&T code, no low-level code.
	 See 386BSD and BSD/386 above.

      NextStep (Next):  BSD over Mach kernel, own GUI.  386 version coming?
         - 1.0

      NEWS-OS (Sony)
         - 3.2

      OSF/1 (DEC): DEC's port of OSF/1

      PC-IX (IBM 8086):  SV

      SCO Xenix (80x86):

      SCO Unix (80x86):  SVR3.2

      Solaris (Sparc, 80386):
         - 1.0:  essentially same as SunOS 4.1.1, with OpenWindows 2.0 and
           DeskSet utilities.
         - 1.0.1:  SunOS 4.1.2 with multiprocessing (kernel not multithreaded);
           not for 386
         - 2.0:  will be based on SVR4 (and have symmetric MP), will include
           support for 386;  with OpenWindows 3.0 (X11R4), DeskSet, ONC, NIS.
           Compilers unbundled!

      SunOS (680x0, Sparc, i386):  based on 4.3BSD, includes much from System V.
         Main Sun achievements: NFS (1984), SunView (1985), NeWS
	 (1986, postscript imaging, now in OpenWindows), OpenLook GUI standard,
	 OpenWindows (NeWS, X11, SunView!).  Newsgroup: comp.sys.sun.*.
         - 3.x:  SV IPC package, FIFOs
         - 4.0.3: lightweight processes, new virtual mem, shared libs
         - 4.1: STREAMS & TLI, 8-bit clean?, async I/O, ms-dos file system
         (continues as Solaris -- see above).

      UHC (80x86): pure SVR4, X11, Motif

      Ultrix (DEC):  based on 4.2BSD with much of 4.3.
         Newsgroup: comp.unix.ultrix.
         - 3.1, 4.0

      UNICOS (Cray):  Newsgroup: comp.unix.cray
         - 5.x, 6,x, 7.0

      UTEK (Tektronix)
         - 4.0

      Xenix (80x86):  1st Unix on Intel hardware, based on SVR2 (previously on
         S III and even V7).  Newsgroup: comp.unix.xenix.

      3B1 (680x0): SV-based, done by Convergent for AT&T.
	 Newsgroup: comp.sys.3b1.

6.7)  Real-time Unices.

      From: "Pierre (P.) Lewis" <lew@bnr.ca>
      Date: Sun, 11 Oct 1992 15:29:00 +0000
      Version: 2.0

      This information is fragmentary.  I doubt all of following are Unices --
         input is welcome.

      RTU (Concurrent), for 68K boxes

      Stellix (Stardent); it's Unix, but is it real-time?

      Velocity (Ready Systems):

      VxWorks (Wind River Systems):  BSDish, no termcap.
         Newsgroup: comp.os.vxworks.

      pSOS??

6.8)  Unix glossary.

      From: "Pierre (P.) Lewis" <lew@bnr.ca>
      Date: Sun, 11 Oct 1992 15:29:00 +0000
      Version: 2.0

      This section provides short definitions of various concepts and
      components of (or related to) Unix systems.

      Chorus: message-passing microkernel, may form basis for a future release
         of SV.  Chorus already have SVR4 running on top (binary-compatible).

      DCE (Distributed Computing Environment, from OSF): Includes RPC (Apollo's
         NCS), directory service (local based on DNS, global on X.500), time,
         security, and threads services, DFS (distrib. file system), ....
         OS-independent.

      DME (Distributed Management Environment, from OSF):  future.

      FFS (Fast File System): alias for UFS (BSD name)

      Mach: modern kernels from CMU (Carnegie Mellon University) on which many
         Unices and other OSs are based (e.g. OSF/1, MacMach, ...):
         - 2.5: monolithic kernel with 4.2BSD
         - 3.0: microkernel with BSD Unix server in user space (and other OSs,
	   e.g. MS-DOS)
         Newsgroup: comp.os.mach

      MFS: Memory File System

      NFS (Network File System):  contributed by Sun to BSD, stateless server

      ONC (Open Network Computing): from Sun(?), includes RPC, name service
	 (NIS aka YP), NFS, ... (found in many Unices, other OSs).

      RFS (Remote File System):  SV, stateful server, incompatible with NFS

      RPC (Remote Procedure Call): high-level IPC (inter-process communication)
         mechanism.  Two flavors.
         - ONC: Over TCP or UDP (later OSI), uses XDR to encode data.
         - DCE: has a different RPC mechanism (based on Apollo's NCS)

      S5 FS:  System V's native file system, blocks 512 to 2K.

      sockets:  BSD interface mechanism to networks (compare TLI).

      STREAMS:  a message-passing kernel mechanism, initially in SVR3, which
         provides a very good interface for protocol development.

      TLI (Transport Library Interface):  SV's interface to transport services
         (TCP, OSI).  UI has also defined an APLI (ACSE/Presentation Library
         Interface)

      UFS (?):  BSD's native file system, blocks 4K to 8K, cylinder groups,
         fragments.

      XTI (X/Open Transport Interface):  TLI with enhancements

6.9)  Acknowledgements.

      From: "Pierre (P.) Lewis" <lew@bnr.ca>
      Date: Sun, 11 Oct 1992 15:29:00 +0000
      Version: 2.0

      (in addition to references): pat@bnr.ca, guy@auspex.com,
      pen@lysator.liu.se, mikes@ingres.com, mjd@saul.cis.upenn.edu,
      root%candle.uucp@ls.com, ee@atbull.bull.co.at,
      Aaron_Dailey@stortek.com.  Many thanks!

-----------------------------

From: "Casper H.S. Dik" <casper@fwi.uva.nl>
Subject: Re: What's wrong with select() ?
Date: 20 Nov 92 08:33:58 GMT
To:       info-unix@sem.brl.mil

bad@flatlin.ka.sub.org (Christoph Badura) writes:

>In <pat.722210144@bcserv> pat@bcserv.wustl.edu (Niemeyer (Pat)) writes:

>>	got = select (1, &fdset, NULL, NULL, &timeout);

>From select(2):

>	  nfound = select(nfds,	readfds, writefds, exceptfds, timeout)
>...
>	  The first nfds descriptors are checked in
>	  each set; i.e. the descriptors from 0 through nfds-1 in the
>	  descriptor sets are examined.

>This means that if you want to check fd 6 with select(2) the first
>parameter has to be at least 6.

7

Casper

-----------------------------

From: M Firat <mzf@castle.ed.ac.uk>
Subject: Loking for a code for GIBBS SAMPLER
Date: 20 Nov 92 12:52:07 GMT
To:       info-unix@sem.brl.mil

Hi,
I am looking for code (including source) which does Gibbs sampling for
variance components of one-way random effect model. Has anyone got this
code for such analysis or is anyone aware of any public domain code for
such analysis ? Preferably the code would be written in C or Fortran 77.


Any assistance would be greatly appreciated. Thank you in advance.

Mehmet Firat
Edinburgh University
Dept. of maths and Stats.
JCMB, 4607
Edinburgh

Tel (031) 650 8575
E-mail  mzf@uk.ac.ed.castle

-----------------------------

From: 00mrfox@leo.bsuvc.bsu.edu
Subject: general unix info needed
Date: 20 Nov 92 12:53:16 GMT
To:       info-unix@sem.brl.mil

could someone please give this unix illiterate some general 
information on unix.  is it as hard to use as i am led to 
believe?  if so what makes it so hard?  i know that there
are *many* different unixes out there--what are the most
commonly used ones?  finally, i have read about svr4.2
which is supposed to be an easier to use unix, is it out
yet?  if not what is the expected release date?  
in need of info :-) !!

-----------------------------

From: Ken McLemore <mclemore@rebec.asd.contel.com>
Subject: make, makefile where s.'s are in another directory, clean solution ?
Keywords: make
Date: 20 Nov 92 14:03:13 GMT
To:       info-unix@sem.brl.mil

we like to keep all our "s." files in one source directory and run makes
in other directory during development, looking for a clean solution for
these "s." dependencies other than an explicit entry for each ".c" that
has macro pathing to the source directory.
suggestions, thanks in advance....ken

-----------------------------

From: Phillip Godwin <cmpsg03@nt.com>
Subject: text search software(follow-up)
Date: 20 Nov 92 14:26:31 GMT
X-Xxmessage-Id: <A7326050B3057889@137.120.253.131.in-addr.arpa>
X-Xxdate: Fri, 20 Nov 92 09:28:48 GMT
X-Useragent: Nuntius v1.1.1d9
To:       info-unix@sem.brl.mil


In my last post...

> I am working on an UNIX-based application (running on HP 400 and 700 
> series workstations) that will among other things allow a user to 
> search a large number of text files for a string.  We had planned
> to parse grep output for the needed search result information, 
> but grep is just too slow.
> 
> What we are looking for is a text search program (commercial or 
> shared) that we can call from within our application.  Does anyone
> out there have any experience with UNIX searching software?  I
> would just like to get an idea of what is out there and then follow
> up on any interesting leads.

I got a couple responses (thanks Ken and Erik), but they led me to the
conclusion that I needed to refine my question.

We've pretty much decided that a non-indexed search will not work
due to the nature of the application. The files that are being 
searched will be updated once per week, and we have off-peak 
machine time that can be used for indexing after the files are
updated. 

Does anyone have any experience with packages that allow indexing 
and searching? I'd also like to hear from anyone who has used dbm or
ndbm for indexing.

If you can help, please email cmpsg03@nt.com.

Thanks...Phil
 -------------------------------------------------
   Phillip Godwin    ||   Northern Telecom    
   cmpsg03@nt.com    ||   Product Verification
   (919) 481-8887    ||   RTP, NC             
 -------------------------------------------------

-----------------------------

From: Phillip Godwin <cmpsg03@nt.com>
Subject: text search software(follow-up)
Date: 20 Nov 92 14:35:13 GMT
X-Xxdate: Fri, 20 Nov 92 09:37:29 GMT
X-Useragent: Nuntius v1.1.1d9
To:       info-unix@sem.brl.mil


In my last post...

> I am working on an UNIX-based application (running on HP 400 and 700 
> series workstations) that will among other things allow a user to 
> search a large number of text files for a string.  We had planned
> to parse grep output for the needed search result information, 
> but grep is just too slow.
> 
> What we are looking for is a text search program (commercial or 
> shared) that we can call from within our application.  Does anyone
> out there have any experience with UNIX searching software?  I
> would just like to get an idea of what is out there and then follow
> up on any interesting leads.

I got a couple responses (thanks Ken and Erik), but they led me to the
conclusion that I needed to refine my question.

We've pretty much decided that a non-indexed search will not work
due to the nature of the application. The files that are being 
searched will be updated once per week, and we have off-peak 
machine time that can be used for indexing after the files are
updated. 

Does anyone have any experience with packages that allow indexing 
and searching? I'd also like to hear from anyone who has used dbm or
ndbm for indexing.

If you can help, please email cmpsg03@nt.com.

Thanks...Phil
 -------------------------------------------------
   Phillip Godwin    ||   Northern Telecom    
   cmpsg03@nt.com    ||   Product Verification
   (919) 481-8887    ||   RTP, NC             
 -------------------------------------------------

-----------------------------

From: Daniel D Suthers <suthers+@pitt.edu>
Subject: Utility for keeping two directories consistent (identical)?
Keywords: directory consistency
Date: 20 Nov 92 15:18:37 GMT
Followup-To: suthers+@pitt.edu
To:       info-unix@sem.brl.mil

Do you know of a utility for keeping the contents of two directories
consistent (identical)?  Or could a shell hacker send me a tcsh
script?

I'm looking for the equivalent of the TI-Explorer
"balance-directories" -- something that checks file dates and copies
them in *either direction* to make the directories consistent.

The point of this: I'm on a distributed file system called AFS. It
goes down a little too often for my tastes. So I keep my work on my
workstation disk as well. I want a script to run at the end of the day
so my work is backed up on AFS.  I also want to be able to edit
remotely on AFS when at home and update the workstation disk when I
come into my office. The "parcel" utility won't do it because it
updates only in one direction (AFS->local). I need something that
doesn't make any assumptions about what machine the directories are
on.

Thanks. Please reply directly to me at suthers+@pitt.edu.


-- 
 ..........................................................................
 Dan Suthers            | LRDC, room 505A
 suthers+@pitt.edu      | 3939 O'Hara Street
 (412) 624-7036 office  | University of Pittsburgh

-----------------------------

From: lpeters <@hq.af.mil (Leslie D Peters):lpeters@postmaster>
Subject: Re: grep
Date: 20 Nov 92 15:37:51 GMT
To:       info-unix@sem.brl.mil


|> >Actually it's Global Regular Expression Parser.
|> I thought it meant Gorns Rarely Eat People...
Grazing Rabbits Excrete Pellets
-- 
/============================================================================\
|                    ___                     |                               |
|       ___....-----'---`-----....___        | I haven't lost my mind --     |
| =========================================  |                               |
|        ___`---..._______...---'___         |  it's backed up on            |
|       (___)      _|_|_|_      (___)        |   tape somewhere.             |
|         \\____.-'_.---._`-.____//          |                               |
|           ~~~~`.__`---'__.'~~~~            | lpeters@marge.hq.af.mil       |
|                   `~~~'                    |                               |
\============================================================================/

-----------------------------

From: snolan <@hq.af.mil (Scott D Nolan):snolan@postmaster>
Subject: Re: grep
Date: 20 Nov 92 15:45:52 GMT
To:       info-unix@sem.brl.mil

|> |> >Actually it's Global Regular Expression Parser.
|> |> I thought it meant Gorns Rarely Eat People...
|> Grazing Rabbits Excrete Pellets
Geraldo Rates Exhibitionist Perverts
-- 
Consistency is the hobgoblin of small minds.

			- Ralph Waldo Emerson

-----------------------------


End of INFO-UNIX Digest
***********************
Newsgroups: comp.unix.questions,comp.unix.misc