# 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

           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.
           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
           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 data base

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

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

## SEE ALSO

           curses(3x), terminfo(5), term(5).