# term 7

    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
           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  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
           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  opti-
           mized  for  retrieval  speed  (unlike the old text-based termcap format
           they replace); to examine an entry, you must use the  infocmp(1m)  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  /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 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
           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 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

           /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).

                                                                           term(7)