# term

## NAME



           term - conventions for naming terminal types
    


## DESCRIPTION



           The environment variable **TERM** should normally contain the type
           name of the terminal, console or display-device type you are
           using.  This information is critical for all screen-oriented
           programs, including your editor and mailer.
    
           A default **TERM** value will be set on a per-line basis by either
           **/etc/inittab**(e.g., System-V-like UNIXes) or **/etc/ttys**(BSD
           UNIXes).  This will nearly always suffice for workstation and
           microcomputer consoles.
    
           If you use a dialup line, the type of device attached to it may
           vary.  Older UNIX systems pre-set a very dumb terminal type like
           “dumb” or “dialup” on dialup lines.  Newer ones may pre-set
           “vt100”, reflecting the prevalence of DEC VT100-compatible
           terminals and personal-computer emulators.
    
           Modern telnets pass your **TERM** environment variable from the local
           side to the remote one.  There can be problems if the remote
           terminfo or termcap entry for your type is not compatible with
           yours, but this situation is rare and can almost always be avoided
           by explicitly exporting “vt100” (assuming you are in fact using a
           VT100-superset console, terminal, or terminal emulator).
    
           In any case, you are free to override the system **TERM** setting to
           your taste in your shell profile.  The tset(1) utility may be of
           assistance; you can give it a set of rules for deducing or
           requesting a terminal type based on the tty device and baud rate.
    
           Setting your own **TERM** value may also be useful if you have created
           a custom entry incorporating options (such as visual bell or
           reverse-video) which you wish to override the system default type
           for your line.
    
           Terminal type descriptions are stored as files of capability data
           underneath terminfo.  To browse a list of all terminal names
           recognized by the system, do
    
                toe | more
    
           from your shell.  These capability files are in a binary format
           optimized for retrieval speed (unlike the old text-based **termcap**
           format they replace); to examine an entry, you must use the
           **infocmp**(1M) command.  Invoke it as follows:
    
                infocmp _entry_name_
    
           where _entry_name_ is the name of the type you wish to examine (and
           the name of its capability file the subdirectory of terminfo named
           for its first letter).  This command dumps a capability file in
           the text format described by terminfo(5).
    
           The first line of a terminfo(5) description gives the names by
           which terminfo knows a terminal, separated by “|” (pipe-bar)
           characters with the last name field terminated by a comma.  The
           first name field is the type's _primary name_ , and is the one to use
           when setting **TERM**.  The last name field (if distinct from the
           first) is actually a description of the terminal type (it may
           contain blanks; the others must be single words).  Name fields
           between the first and last (if present) are aliases for the
           terminal, usually historical names retained for compatibility.
    
           There are some conventions for how to choose terminal primary
           names that help keep them informative and unique.  Here is a step-
           by-step guide to naming terminals that also explains how to parse
           them:
    
           First, choose a root name.  The root will consist of a lower-case
           letter followed by up to seven lower-case letters or digits.  You
           need to avoid using punctuation characters in root names, because
           they are used and interpreted as filenames and shell meta-
           characters (such as !, $, *, ?, etc.) embedded in them may cause
           odd and unhelpful behavior.  The slash (/), or any other character
           that may be interpreted by anyone's file system (\, $, [, ]), is
           especially dangerous (terminfo is platform-independent, and
           choosing names with special characters could someday make life
           difficult for users of a future port).  The dot (.) character is
           relatively safe as long as there is at most one per root name;
           some historical terminfo names use it.
    
           The root name for a terminal or workstation console type should
           almost always begin with a vendor prefix (such as **hp** for Hewlett-
           Packard, **wy** for Wyse, or **att** for AT&T terminals), or a common name
           of the terminal line (**vt** for the VT series of terminals from DEC,
           or **sun** for Sun Microsystems workstation consoles, or **regent** for
           the ADDS Regent series.  You can list the terminfo tree to see
           what prefixes are already in common use.  The root name prefix
           should be followed when appropriate by a model number; thus **vt100** ,
           **hp2621** , **wy50**.
    
           The root name for a PC-Unix console type should be the OS name,
           i.e., **linux** , **bsdos** , **freebsd** , **netbsd**.  It should _not_ be **console** or
           any other generic that might cause confusion in a multi-platform
           environment!  If a model number follows, it should indicate either
           the OS release level or the console driver release level.
    
           The root name for a terminal emulator (assuming it does not fit
           one of the standard ANSI or vt100 types) should be the program
           name or a readily recognizable abbreviation of it (i.e.,
           **versaterm** , **ctrm**).
    
           Following the root name, you may add any reasonable number of
           hyphen-separated feature suffixes.
    
           2p   Has two pages of memory.  Likewise 4p, 8p, etc.
    
           mc   Magic-cookie.  Some terminals (notably older Wyses) can only
                support one attribute without magic-cookie lossage.  Their
                base entry is usually paired with another that has this
                suffix and uses magic cookies to support multiple attributes.
    
           -am  Enable auto-margin (right-margin wraparound).
    
           -m   Mono mode - suppress color support.
    
           -na  No arrow keys - termcap ignores arrow keys which are actually
                there on the terminal, so the user can use the arrow keys
                locally.
    
           -nam No auto-margin - suppress am capability.
    
           -nl  No labels - suppress soft labels.
    
           -nsl No status line - suppress status line.
    
           -pp  Has a printer port which is used.
    
           -rv  Terminal in reverse video mode (black on white).
    
           -s   Enable status line.
    
           -vb  Use visible bell (flash) rather than beep.
    
           -w   Wide; terminal is in 132-column mode.
    
           Conventionally, if your terminal type is a variant intended to
           specify a line height, that suffix should go first.  So, for a
           hypothetical FuBarCo model 2317 terminal in 30-line mode with
           reverse video, best form would be **fubar-30-rv**(rather than, say,
           “fubar-rv-30”).
    
           Terminal types that are written not as standalone entries, but
           rather as components to be plugged into other entries via **use**
           capabilities, are distinguished by using embedded plus signs
           rather than dashes.
    
           Commands which use a terminal type to control display often accept
           a -T option that accepts a terminal name argument.  Such programs
           should fall back on the **TERM** environment variable when no -T
           option is specified.
    


## PORTABILITY



           For maximum compatibility with older System V UNIXes, names and
           aliases should be unique within the first 14 characters.
    


## FILES



           terminfo/?/*
                compiled terminal capability database
    
           /etc/inittab
                tty line initialization (AT&T-like UNIXes)
    
           /etc/ttys
                tty line initialization (BSD-like UNIXes)
    


* * *