


TERM(7)                                                   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  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 (Linux and  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 ter-
       minal 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  emula-
       tors.

       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 set-
       ting 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 capabil-
       ity data underneath /usr/share/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(1) command.  Invoke it as fol-
       lows:

            infocmp entry-name



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TERM(7)                                                   TERM(7)


       where entry-name is the name of the type you wish to exam-
       ine  (and the name of its capability file the subdirectory
       of /usr/share/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 pri-
       mary 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 let-
       ters or digits.  You need to avoid using punctuation char-
       acters  in  root  names,  because they are used and inter-
       preted 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 ter-
       minals), or a common name of the terminal line (vt for the
       VT  series of terminals from DEC, or sun for Sun Microsys-
       tems workstation consoles, or regent for the  ADDS  Regent
       series.   You  can list the terminfo tree to see what pre-
       fixes 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 fol-
       lows, it should indicate either the OS  release  level  or
       the console driver release level.



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TERM(7)                                                   TERM(7)


       The root name for a terminal emulator (assuming it doesn't
       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



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TERM(7)                                                   TERM(7)


       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
       /usr/share/terminfo/?/*
            compiled terminal capability database

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

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

SEE ALSO
       curses(3), terminfo(5), term(5).






































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