term

term(7)                Miscellaneous Information Manual                term(7)

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  in-
       formation  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  con-
       soles.

       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 sit-
       uation is rare and can almost always be avoided by explicitly exporting
       "vt100"  (assuming you are in fact using a VT100-superset console, ter-
       minal, 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  un-
       derneath  /etc/terminfo.  To browse a list of all terminal names recog-
       nized by the system, do

            toe | more

       from your shell.  These capability files are in a binary  format  opti-
       mized  for  retrieval  speed  (unlike the old text-based termcap format
       they replace); to examine an entry, you must use  the  infocmp(1)  com-
       mand.  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 /etc/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 compat-
       ibility.

       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  let-
       ter  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  plat-
       form-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 Mi-
       crosystems workstation consoles, or regent for the ADDS Regent  series.
       You can list the terminfo tree to see what prefixes are already in com-
       mon 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 read-
       ily 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  sup-
            port 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 speci-
       fied.

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

FILES
       /etc/terminfo/?/*
            compiled terminal capability data base

       /etc/inittab
            tty line initialization (AT&T-like UNIXes)

       /etc/ttys
            tty line initialization (BSD-like UNIXes)

SEE ALSO
       ncurses(3NCURSES), terminfo(5), term(5).

                                                                       term(7)