LINUX Administrator’s
Quick Reference Card

/etc/rc.d/rc.netdevice/etc/modules.conf

Jialong He
Jialong_he@bigfoot.com
http://www.bigfoot.com/~jialong_he

User Management
Files/etc/group/etc/passwd/etc/shadow

User account information.

/etc/bashrc/etc/profile$HOME/.bashrc$HOME/.bash_profile

BASH system wide and per user init files.

/etc/HOSTNAME/etc/NETWORKING(Slackware)/etc/sysconfig/network(Redhat)Put network card driver (e.g., e100) in“rc.netdevice”/sbin/modprobe e100
Or in “modules.conf”
alias eth0 e100
hostname is set by “/bin/hostname” during
boot and the name is read from these files.
May change manually.

NFS server export list.

/etc/auto.masterauto mount master file.

/etc/hosts

host name to IP mapping file.

Commands

host name information look up order.
Example:order hosts, bindmulti onmount

mount a file system or all entries in fstab.

/etc/host.conf

exportfs

export file system listed in exports

showmount –ehostnameshow file systems exported

etc/resolv.conf

new way to specify information source.

/etc/skel

template files for new users.

TCP/IP services and ports mapping.

/etc/default

default for certain commands.

/etc/rpc/etc/redhat-release/etc/slackware-version

Redhat and Slackware version info (Linuxkernel version with “uname –a”)

create, delete, modify an new user or update
default new user information..

newusers

add, delete or modify group.

chage. chfn, chshmodify account policy (password length,
expire data etc.) or finger information (fullname, phone number etc.) change default login
shell.

linux init=/bin/sh rw
makebootdisk

gain root access during boot prompt without
password, can be used to fix some problems.
mount –w -n –o remount /make a bootable floppy disk

RPC service name to their program numbers
mapping.

Commands
netconfig

menu driven Ethernet setup program.

pppsetup

setup PPP connection (Slackware).
setup Ethernet during boot, for example/sbin/ifconfig eth0 ${IPADDR} broadcast${BROADCAST} netmask ${NETMASK}

update and create new users (batch mode).

groupadd, groupdel,groupmodifconfig

host/etc/printcap/etc/printcap.local

Printer capabilities data base.

/etc/lpd.conf

LPRng configuration file.

/etc/lpd.perms

permissions control file for the LPRng line
printer spooler/etc/hosts.lpd

Access control (BSD lpd).

/etc/hosts.equiv

trusted hosts.

PRINTER

Environment variable of default printer.

/dev/lp0

parallel port.

Commands/sbin/route add default gw ${GATEWAY} netmask
0.0.0.0 metric 1

lpc, lpq, lprm

lookup host name or IP (similar to nslookup).

dnsdomainname show DNS domain name.
arping; arp

find out Ethernet address by first arping then arp.

ipchains

firewall and NAT (/etc/sysconfig/ipchains on Redhat)

iptablesfirewall and NAT (/etc/sysconfig/iptables on Redhat)

ntsysvmenu driven SYSV service configuration (Redhat)

chkconfig

command line SYSV service configuration (Redhat)/etc/rc.d/rc.inet1(Slackware)/etc/sysconfig/neworkscripts/ifcfg-eth0 (Redhat)

Redhat files in /etc/sysconfig
Configuration Files
keyboard

Printer Configuration
Files/sbin/route add -net ${NETWORK} netmask${NETMASK} eth0

Network Configuration
Files
IP address, Network mask, Default gateway
are in these files. May edit manually tomodify network parameters.

NFS File Sharing
Files
file systems mounted during boot.

/etc/networks/etc/protocols/etc/services

useradd, userdel,
usermod

network settings, contains
NETWORKING=yes
HOSTNAME=hostname.domain.com/etc/exports/etc/nsswitch.conf

script to create an new user interactively(slackware) or link to useradd (Redhat).

network/etc/fstab

TCSH system wide and per user init files.

adduserMouse type, e.g.,
MOUSETYPE=Microsoft
XEMU3=yes

specify name server, DNS domain andsearch order. For Example:
search la.asu.edu
nameserver 129.219.17.200/etc/csh.cshrc/etc/csh.login$HOME/.cshrc$HOME/.tcshrc$HOME/.login

Commands

mouse

keyboard map, e.g.,
KEYBOARD=”/usr/lib/kdb/keytables/us.map”

line printer control program, print queue
maintain

SendmailFiles
sendmail.cf
sendmail.mc“sendmail.cf” is the configuration file. “sendmail.mc” isa macro file which can be used to generate “sendmail.cf”
by: m4 sendmail.mc > sendmail.cf

aliasesmail aliases, must run “newaliases” after change. use:include: to include external list in a file.

.forward

per user aliases, use \yourname to prevent further expand
and keeps a copy in mailbox.

accessmail access control, FEATURE(access_db) should be set
in sendmail.mc. For example, in /etc/mail/accesscyberpromo.com REJECT
mydomain.com RELAY

spam@somewhere.com DISCARD
makemap hash /etc/mail/access < /etc/mail/access/etc/mail/relaylist all host/domain accepted for relaying.
domains/boot/System.map

Compile Modules
make modules
make modules_install

Building and installing modules.

Manage Modules

Commands
newaliases

rebuild the data base for the mail aliases file.

makemapbuild access database, e.g,
makemap hash access.db<access

Useful Configuration Files
Files
httpd.conf

Apache web server configuration file.

lilo.conf

LILO boot loder configuration file.

insmod, lsmod, modinfo,
Manage loadable modules.
modprobe, rmmod,
depmodMiscellaneousFiles/etc/shells

allowed login shells/etc/ftpusers

user names NOT allowed to use ftp.

/etc/hosts.allow/etc/hosts.deny

TCP wrapper access control files.

/etc/sysconfig(redhat)contains system configuration files.

syslog.conf

System log daemon (syslogd) configuration.

ssh_config
sshd_config

SSH client and server configuration files.

ld.so.conf

default dynamic library search path (runldconfig).

/dev/fd0

floppy drive A

mtools.conf

mtool configuration file (access DOS file).

/etc/inittab/etc/init.d

system run level control file.

named.conf

DNS name server (BIND).

sysctl.conf

kernel parameters by sysctl (Redhat).

ntp.conf

net time server.

inetd.conf

Internet super server.

Xinetd.conf, Xinet.ddirectory

Extended inetd configuration.

proftpd.conf

proftpd FTP server.

amanda.conf

network backup server.

/etc/pine.conf/etc/pine.conf.fixed

PINE mail client system wide settings.

Rebuild Kernel
Configure Kernel Parameters
make config
make menuconfig
make xconfig

Unpack the tarball in /usr/src directorybzip2 -dc linux-2.4.0.tar.bz2 | tar xvf –Configuring the kernel with interactive, menu
or X window interface.

Compile Kernel Source
Building and installing a new kernel.
make dep
make zImage
make zdisk
make zlilo
make bzImage

cp arch/i386/boot/bzImage /boot/bzImageKERNEL_VERSION
cp System.map /boot/System.mapKERNEL_VERSIONln -s /boot/System.map-KERNEL_VERSION

Commands
fromdos, todos(Slackware)convert text file from/to linux format.
dos2unix, unix2dos(Redhat)nmap

scan a host for opened ports.

crontabshow or edit cron jobs.

sys-unconfig

unconfigure systemchkconfig --list

list services started at different run level.

unset TMOUT

disable BASH auto-logout feature

unset autologout

disable TCSH auto-logout featurekudzu

probe for new hardware (Redhat).

Rpm

rpm -i INSTALL a package
rpm -e UNINSTALL a package
rpm -q QUERY a package
rpm -U UPDATE a package

man cmd | col –b>cmd.txt
ntop –w 3000

save a man page as a text file and remove control
characters.
Run ntop and listen on web port 3000. View trafficwith browser to http://hostsname:3000

Configure Apache 2.0 with SSL
mod_ssl(1)

when compile apache, specify –enable-ssl for configure script.
By default, ssl is not enabled. After compiling, use “httpd –l”
to list the modules. “mod_ssl” should be in them.
(2) generate private key with command:
openssl genrsa -out server.key 1024
(3)

generate certificate request
openssl req -new -key server.key -out server.csr

pwck, grpck

verify integrity of password and group files.

pwconv,
pwunconv,
grpconv,
grpuncov

convert to and from shadow passwords and groups.

shadowconfig

toggle shadow passwords on and off.

quota,
edquota,quotacheck,quotaon,quotaoff,
repquota,

Manage disk quota.

(*) Trouble shoot SSl connection with command
openssl s_client –connect yourhost.yourdomain.com:443

lilo -D dos

set LILO default OS (default=dos in lilo.conf)

Syslog.conf

ldd

find out shared library dependencies.

lsof

list opened files.

fuser filename

show processes that using the file.

ifdownifup

bring up/down a network interface (Redhat)

sysctlconfigure kernel parameters (Redhat).

socklist

list opened socked.

shutdown [–r|h]now

reboot / halt computer(4) generate self-signed certificate
openssl x509 -req -days 60 -in server.csr -signkey server.key -out
server.crt(5) modify “ssl.conf” which is included in “httpd.conf”. To start web
server with SSL support , use “httpd –DSSL” or “apachectl startssl”,
otherwise, commented out <IfDefine SSL> in ssl.conf.

Each line consists of a selector and an action. A selector has two parts:
facilities and priorites, separated by a period (.),You may precede every
priority with an equation sign (``='') to specify only this single priority
and not any of the above. You may also (both is valid, too) precede thepriority with an exclamation mark (``!'') to ignore all that priorities, either
exact this one or this and any higher priority.

Example:mail.notice*.emerg/var/log/mail # log to a file
@myhost.mydomain.org# log to remote hostNote: separator between first column and second colume (log file name)must be TAB, not spaces.

http://localhost:631

CUPS web administration interface

lpadm –d myprint
lpadm –x myprint-d option set default printer-x option delete a installed printer.

enable/disable
accept/rejectControl printing queue

security = user
In this (default) security mode, samba maintain its own user login databasewhich is usually in /etc/samba/smbpasswd. This file is created withcommand /usr/sbin/smbpasswd. Note, the user login file and command havethe same name but in different directories. Following settings are used:

Facilities

auth, auth-priv, cron, daemon, kern, lpr, mail, mark,news, syslog, user, uucp, local0 – local7.

lpadmin –p myprint –P
another.PPD

Change PPD file

Priorities

debug, info, notice, warning, err, crit, alert, emerg.

lpoptions –p myprint -l

Display associate PPD

Regular File:
File with full pathname beginning with “/”.

lpinfo –v

List supported printing protocols

lp –d myprint filename
lpr –P myprint filename

Print a filecancel id
lprm idremove a print job from queue/etc/cups/printers.conf/etc/cups/classes.conf/etc/cups/cupsd.conf

CUPS related configuration files

security = server
Use another computer (NT or W2k) to authenticate users. No need to join adomain. Need to specify a login server:
password server = mywin.domain.com

Introduction/etc/cups/usr/lib/cups/usr/share/cups

CUPS related directories

security = share
Give each share a password, no user name needed.

Common Unix Printing System (CUPS) is the default printing system on
many Linux distros and Mac OSX. The latest version can be downloaded
from http://www.cups.org. You have to download CUPS package andoptionally ESP Ghostscript package if you don’t have a Postscript printer.

Samba File and Printer Sharing

ActionTerminal and Console:
Specify a tty, same with /dev/console.
Remote Machine:@myhost.mydomain.org

Printing with CUPS

You compile and install both packages with commands
configure; (see configure –help)
make;
make install
The printing daemon “/usr/sbin/cupsd” is controlled by a configuration file“/etc/cups/cupsd.conf”. The syntax of this file is similar to Apache’s
httpd.conf. You can edit this file with a text editor, but normally the default
settings work fine. After change any configuration, you restart “cupsd” to let
it read new settings (for example: rc.cups start).
Another important configuration file is “Printers.conf”. This file defines
each local or network (socket or IPP) printer. You can edit this file with atext editor and then restart “cupsd” to have it read the new settings. Anotherway to change printer settings is to use command line program “lpadmin”.
CUPS has a web-based administration tool. You point a web browser tohttp://localhost:631. Each Linux distribution also has its own GUI printeradministration tool.
lpadmin -p myprint -E -v parallel:/dev/lp0 –m laserjet.ppd
lpadmin -p myprint -E -v socket://11.22.33.44 -m myprint.ppd
lpadmin -p myprint -E -v lpd://11.22.33.44/ -m myprint.ppd
lpadmin -p myprint -E -v ipp://11.22.33.44/ -m myprint.ppd
lpadmin -p myprint -E -v ipp://user:passwd@11.22.33.44/ -m
myprint.ppd
The about commands add a printer connected to (1) local parallel port, (2)JetDirect printer, and (3) LPD printer. –m option specifying a Postscript
Printing Definition (PPD) files. CUPS has a few PPD files preinstalled. Inorder to use full features of your printer, you may need to find a proper PPD
file and put it in “/usr/share/cups/model” directory.
kcmshell printmgr

KDE printer manager

Introduction
Samba provides file and printer sharing with MS Windows computers. It
makes UNIX speaks SMB/ICFS file and printer sharing protocol. The latest
version of samba can be downloaded fromhttp://www.samba.org.
Samba is controlled by a configuration file “smb.conf”. On Redhat Linux,
one can use “redhat-config-samba” to modify the configuration file. On
other systems, SWAT is a web based GUI interface. SWAT is run from“inetd” and listen to port 901. You just need point your browser tohttp://localhost:901 after starting swat.

encrypt passwords = yes
smb passwd file = /etc/samba/smbpasswd
security = domain
In this security mode, samba server must join to an NT domain (using net
command) and authenticate users by a domain controller. A user must haveboth valid UNIX and NT account in order to access files.

IPtables (Netfilter)
Command Syntax
iptables [-t <table >] <command> <chain > <parameters>
Save and Restore rules/sbin/iptables-save > /etc/sysconfig/iptables/sbin/iptables-restore < /etc/sysconfig/iptables
Firewall script sample
http://tiger.la.asu.edu/iptables_examples.htm

Build-in Table
filterThis is the default table for handling network packets. Buildin chains are:1.
INPUT — This chain applies to packets received
via a network interface.
2.
OUTPUT — This chain applies to packets sentout via the same network interface which received
the packets.
3.
FORWARD — This chain applies to packets
received on one network interface and sent out onanother.

natThis table used to alter packets that create a new connection.
Build-in chains:
1.
PREROUTING — This chain alters packets
received via a network interface when they arrive.
2.
OUTPUT — This chain alters locally-generated
packets before they are routed via a network
interface.
3. POSTROUTING — This chain alters packets
before they are sent out via a network interface.
## Masquerade everything out ppp0.
iptables -t nat -A POSTROUTING -o ppp0 -j
MASQUERADE

Commands
To test if the syntax of “smb.conf” is correct, use
testparm smb.conf
List shares on a Samba or Windows server
smbclient –L machinename -U username
Connect to a Samba or Windows server and get/put files using FTP likecommands:
smbclient //machinename/sharename -U username

Security Mode in “smb.conf”

## Change source addresses to 1.2.3.4.
iptables -t nat -A POSTROUTING -o eth0 -j SNAT --to1.2.3.4
mangleThis table is used for specific types of packet alteration.
Build-in chains:
1.
PREROUTING — This chain alters packets
received via a network interface before they arerouted.
2. OUTPUT — This chain alters locally-generated
packets before they are routed via a network
interface.

Commands--flush | -F

Flush (delete) rules in the selected chain.

--policy | -P

Set default policy for a particular chain.

--list | -L

List all rules in filter table, use [–t tablename] tospecify other tables.

--append | -A

A appends a rule to the end of the specified chain.

-insert | -I

Inserts a rule in a chain at a particular point.

Other commands:(1) --new | -N (2) --delete | -D (3) --replace | -D (4) --zero | -Z(5) –check | -C(6) delete-chain | -X(7) rename-chain | -E

list byiptables –p icmp -h

Option for state module (-m state --state)
ESTABLISHED

The matching packet is associated with otherpackets in an established connection.

RELATED

The matching packet is starting a new connection
related in some way to an existing connection.

NEW

The matching packet is either creating a newconnection or is part of a two-way connection notpreviously seen.

INVALID

The matching packet cannot be tied to a known
connection.

X Window (XFree86)
Files

XFree86 uses a configuration file called XF86Config for its initial setup.
This file is normally located in “/etc/X11” or “/etc” directory. The
XF86Config file is composed of a number of sections which may bepresent in any order. Each section has the form:
Section "SectionName"
SectionEntry...
EndSection
The graphics boards are described in the Device sections, and the monitors
are described in the Monitor sections. They are bound together by a Screen
section. Keyboard and Mouse are described in InputDevice sections,although Keyboard and Pointer are still recognized. ServerLayout section
is at the highest level and bind together the InputDevice and Screen
sections.

To set screen resolution, in “Screen” section and Subsection “Display”,
specify a mode. For example: Modes “1024x768”

A special keyword called Option may be used to provide free-form data tovarious components of the server. The Option keyword takes either one or
two string arguments. The first is the option name, and the optional second
argument is the option value. All Option values must be enclosed in quotes.

To specify screen refresh rate, in “Monitor” section, specify vertical rate.
For example: VertRefresh 70-120

File Section
FontPath "path"
Font path elements may be either absolute directory paths, or a font server
identifier--proto | -p [!] nameprotocol: by number or name, including tcp,
udp, icmp or all.

$HOME/.xinitrc/etc/X11/xinit/xinitrc/etc/X11/xinit/xinitrc.d scripts run after X server started$HOME/.Xclients/etc/X11/xinit/Xclients--source | -s [!] addr/masksource IP address.

/etc/sysconfig/desktop

decide which desktop (GNORM, KDE) to start(Redhat). (by /etc/X11/prefdm)/etc/X11/fs/config

configuration of X11 font path (font server).

Parameters

XF86Config (xorg.conf)--destination | -d addr/mask destination IP address.

RGBPath "path"
Sets the path name for the RGB color database.
ModulePath "path"
Allows you to set up multiple directories to use for storing modules loadedby the XFree86 server.

--in-interface | -i

incoming interface name, e.g. eth0 or ppp0.

--out-interface | -ooutgoing interface name.

Commands--jump | -jjump to a particular target when matching arule. Standard options: ACCEPT, DROP,QUEUE, RETURN, REJECT. May jump
to a user defined chain.

startxstart X window system.

Xconfigurator(Redhat)xfree86setup(Slackware)
xf86config

EXAMPLE
Section "Files"
RgbPath "/usr/X11R6/lib/X11/rgb"
FontPath "unix/:7100"
EndSection

setup X server and generate XF86config.

Serverflags Section

XFree86 -configure

XFreee86 auto configuration (Plug-n-Play),
generate a template named “XF86Config.new”

Ctrl+Alt+Del

stop X server (on some system Ctrl+Alt+ESC).

Ctrl+Alt+F1
Ctrl+Alt+F7

F1 temporary switch to text mode, F7 switch
back to graphic mode.

SuperProbe

detect graphic hardware.

Match SYN packets.

xvidtuneadjust X server origin and size.

Match TCP packets with specific bits set. For example, -p
tcp –tcp-flags ACK,FIN,SYN SYN will only match TCP
packets that have the SYN flag set and the ACK and FIN
flags unset.

xmodmap

modifying key map and mouse button map.

xhost

server access control program for X.

xsetroot

root window parameter setting utility for X.

xlsfonts

server font list displayer for X.

xset

ser preference utility for X.

match second or further fragments only.

--fragment | -f

Options for TCP and UDP protocol--sport | --source-port--dport | destination-portsource and/or destination port. Can specify arange like 0:65535, use exclamation
character (!) to NOT match ports.

Options for TCP only--syn--tcp-flags

Options for ICMP only--icmp-type [!] type

Match specified ICMP type. Valid ICMP type can be

Option "DontZap" "boolean"
Disable use Ctrl+Alt+Backspace to terminate X server.
Option "DontZoom" "boolean"
Disable use ‘Ctrl+Alt+Keypad +’ and ‘Ctrl+Alt+Keypad -’ to switch videomode.
Option "BlankTime" "time"
Sets the inactivity timeout for the blanking phase of the screensaver inminutes. Default 10 min.
Option "StandbyTime" "time"
Sets the inactivity timeout for the "standby" phase of DPMS mode inminutes. Default 20 min.
Option "SuspendTime" "time"
Sets the inactivity timeout for the "suspend" phase of DPMS mode, default
30 min.
Option "OffTime" "time"
Sets the inactivity timeout for the "off" phase of DPMS mode, default 40
min.

Option "DefaultServerLayout" "layout_id"
Specify the default ServerLayout section to use. Default is the first
ServerLayout section.

Specifies information about the video card used by the system. You musthave at least one Device section in your configuration file. The active device
is in ServerLayout->Screen.

DISPLAY SUBSECTION
Each Screen section must have at least one Display Subsection whichmatches the depth values in DefaultDepth.

EXAMPLE
Section "ServerFlags"
Option "BlankTime" "99999"
Option "StandbyTime" "99999"
Option "SuspendTime" "99999"
Option "OffTime" "99999"
EndSection

Identifier
Specify an unique name for this graphics card.

Depth depthThis entry specifies what color depth of this Display Subsection.

DriverSpecify the name of the driver to use for this graphics card.

Virtual xdim ydim
Specifies the virtual screen resolution to be used.
ViewPort x0 y0
Sets the upper left corner of the initial display.

Module Section

EXAMPLE
Section "Device"
Identifier"ATI Mach64"
VendorName "ATI MACH64"
VideoRam
2048
EndSection

Load "modulename"Load a module. The module name given should be the module's standard
name, not the module file name.

Monitor Section

EXAMPLE
Section "Module"
Load"extmod"Load"type1"EndSection

Monitor section describes a monitor. There must be at least one monitor
section and the active one is used in ServerLayout->Screen.
Identifier
Specify an unique name for this monitor.
HorizSync horizsync-range
Gives the range(s) of horizontal sync frequencies of this monitor in kHz.

InputDevice Section
There are normally at least two InputDevice sections, one for Keyboard and
one for Mouse.
Identifier
Specify an unique name for this input device.
DriverSpecify the name of the driver to use for this input device..
Option "CorePointer"
This input device is installed as the primary pointer device.

VertRefresh vertrefresh-range
Gives the range(s) of vertical sync frequencies of this monitor in Hz.
EXAMPLE
Section "Monitor"
Identifier "Generic Monitor "VendorName "Monitor Vendor"
ModelName "Monitor Model"
HorizSync 31.5-56.6
VertRefresh 40-70
EndSection

Option "CoreKeyboard"This input device is the primary Keyboard.
EXAMPLE
Section "InputDevice"
Identifier"Generic Keyboard"
Driver"keyboard"
Option "AutoRepeat" "500 30"
Option"CoreKeyboard"
EndSection
Section "InputDevice"
Identifier"PS2 Mouse"
Driver"mouse"Option"CorePointer"
Option"Device""/dev/mouse"
Option"Protocol""PS/2"
Option"Emulate3Buttons" "true"
EndSection

Device Section

Modes "mode-name" ...
Secifies the list of video modes to use. Each mode-name specified must be
in double quotes. They must correspond to those specified in the appropriate
Monitor section (including implicitly referenced built-in ESA standard
modes). mode can be switched with Ctrl+Alt+Keypad-Plus or
Ctrl+Alt+Keypad-Minus.
EXAMPLE
Section "Screen"
Identifier "My Screen”
Device " ATI Mach64"
Monitor " Generic Monitor"
DefaultDepth 16
SubSection "Display"
Depth 16
Modes "1024x768" "800x600" "640x480"
EndSubSection
SubSection "Display"
Depth 24
Modes "1024x768" "800x600" "640x480"
EndSubSection
EndSection

ServerLayout Section

Screen Section binds Device and Monitor sections. There must be at least
one Screen Section. The active one is in ServerLayout section.

ServerLayout section binds a Screen section and one or more InputSection
to form a complete configuration. The active ServerLayout section is
specified in ServerFlags. If not, the first ServerLayout section is active. If noServerLayout sections are present, the single active screen and two active(core) input devices are selected as described in the relevant sections.

Identifier
Specify an unique name for this Screen Section.

Identifier
An unique name for this ServerLayout Section.

Device "device-id"
This specifies the Identifier of Device section to be used for this screen.

Screen screen-num "screen-id" position-information
The screen-id field is mandatory, and specifies the Screen section beingreferenced.

Screen Section

Monitor "monitor-id"
This specifies the Identifier of Monitor section to be used for this screen.
DefaultDepth depth
Default color depth, like 8, 16 or 24.
Option "Accel"
Enables XAA (X Acceleration Architecture), default is ON.

InputDevice "idev-id" "option" ...
Normally at least two are required, one for the core pointer and the other forthe primary keyboard devices.
EXAMPLE
Section "ServerLayout"
Identifier"Default Layout"
Screen"My Screen"
InputDevice "Generic Keyboard"
InputDevice "PS/2 Mouse"
EndSection

Boot Sequences
RedhatMore Linux distributions are using GRUB as the boot loader instead of
LILO. GRUB can be downloaded from http://www.gnu.org/software/grub/

Usually the Linux kernel file is /boot/vmlinuz and is loaded by a bootloder (e.g., LILO). The first process created by the kernel is /sbin/init. It
uses a configuration file /etc/inittab. init process runs /etc/rc.d/rc.sysinit
script first, then runs all scripts in /etc/rc.d/rcN.d, where N is the default
run level defined in inittab. The actual scripts are stored in /etc/rc.d/init.d
and proper links are created in run level directoris to point tocorresponding scripts in init.d directory. The last script to run is/etc/rc.d/rc.local.

The newer version of GRUB (called GRUB2) is totally rewritten and uses
somewhat different syntax than Ver 0.xxx (called GRUB Legacy). Afterunpacking GRUN, compile and install it with following commands:./configure
makemake install

Run level 1: Single user mode
Run level 3: Multiuser mode
Run level 5: Multiuser model with X11

grub-install /dev/fd0

Slackware
In Slackware, Linux kernel is /boot/vmlinuz and the first process started
by the kernel is /sbin/init. Its configuration file is /etc/inittab. init firstruns script /etc/rc.d/rc.S, then runs /etc/rc.K for single user mode or/etc/rc.M for multiuser mode. The last script to run is /etc/rc.d/rc.local.
rc.S calls scripts (rc.modules, rc.pcmcia, rc.serial and rc.sysvinit).
rc.M calls scripts (rc.inet1, rc.inet2, rc.httpd, rc.samba) and start some
network server (lpd, httpd etc.)
rc.inet1 sets IP address, Mask, and default Gateway.
Run level 1: Single user mode
Run level 3: Multiuser mode
Run level 4: Multiuser model with X11

Fix Slackware boot after Ghost••••boot with slackware installation CD
mount root partition (mount /dev/hda2 /mnt)
change root (chroot /mnt)
re-run LILO (cd /mnt/etc; lilo)First test GRUB by creating a bootable floppy disk with command

Suppose you have Windows installed on the first hard disk and Linux on
the second disk, boot with just created floppy, when grub> prompt
appears, type following commands=== Boot Linux ===grub> root (hd1,0)
grub> kernel /boot/vmlinuz(or linux /boot/vmlinuz if using GRUB2)
grub> boot=== Boot Windows ===grub>rootnoverify(hd0, 0)
chainloader +1
bootOther Useful GRUB commands
ls

Display disks and partitions (GRUB2)

geometry(hd0)Show hard disk geometry, test if HD exist

configfile
Display boot menu
(hd1,0)/boot/grub/grub.confcat (hd1, 0)/etc/fstab

Display a file content, can figure out which
partition was used as root partition in an
unbootable system, then pass root parameterin “kernel” command

GRUB boot loader

help

List available commands

Introduction

Sample GRUB configuration file#===================# GRUB ver 0.xxx#===================
default=0
timeout=10
splashimage=(hd1,2)/grub/splash.xpm.gz
title Linuxroot (hd1,0)kernel /boot/vmlinuz root=/dev/sdb1
title Windows XP
rootnoverify (hd0,0)
chainloader +1#===================# GRUB2#===================
set timeout=10
set default=0# Entry 0 - Load Linux kernel
menuentry "Linux" {set root=(hd1,0)
linux /boot/vmlinuz root=/dev/hda2
initrd /initrd}# Entry 1 - Chainload another bootloader
menuentry "Windows" {set root=(hd0,0)
chainloader +1}