1term(7)                Miscellaneous Information Manual                term(7)


6       term - conventions for naming terminal types


9       The  environment variable TERM should normally contain the type name of
10       the terminal, console or  display-device  type  you  are  using.   This
11       information  is  critical  for  all screen-oriented programs, including
12       your editor and mailer.
14       A default TERM value  will  be  set  on  a  per-line  basis  by  either
15       /etc/inittab  (e.g.,  System-V-like  UNIXes) or /etc/ttys (BSD UNIXes).
16       This will nearly always suffice for workstation and microcomputer  con‐
17       soles.
19       If  you  use a dialup line, the type of device attached to it may vary.
20       Older UNIX systems pre-set a very dumb terminal  type  like  “dumb”  or
21       “dialup”  on  dialup lines.  Newer ones may pre-set “vt100”, reflecting
22       the prevalence of DEC VT100-compatible terminals and  personal-computer
23       emulators.
25       Modern  telnets pass your TERM environment variable from the local side
26       to the remote one.  There can be problems if  the  remote  terminfo  or
27       termcap entry for your type is not compatible with yours, but this sit‐
28       uation is rare and can almost always be avoided by explicitly exporting
29       “vt100”  (assuming you are in fact using a VT100-superset console, ter‐
30       minal, or terminal emulator.)
32       In any case, you are free to override the system TERM setting  to  your
33       taste in your shell profile.  The tset(1) utility may be of assistance;
34       you can give it a set of rules for deducing or  requesting  a  terminal
35       type based on the tty device and baud rate.
37       Setting  your  own  TERM value may also be useful if you have created a
38       custom entry incorporating options (such as  visual  bell  or  reverse-
39       video)  which  you  wish  to  override the system default type for your
40       line.
42       Terminal type descriptions are  stored  as  files  of  capability  data
43       underneath /usr/share/terminfo.  To browse a list of all terminal names
44       recognized by the system, do
46            toe | more
48       from your shell.  These capability files are in a binary  format  opti‐
49       mized  for  retrieval  speed  (unlike the old text-based termcap format
50       they replace); to examine an entry, you must use the  infocmp(1M)  com‐
51       mand.  Invoke it as follows:
53            infocmp entry_name
55       where  entry_name  is the name of the type you wish to examine (and the
56       name of its capability file  the  subdirectory  of  /usr/share/terminfo
57       named  for  its first letter).  This command dumps a capability file in
58       the text format described by terminfo(5).
60       The first line of a terminfo(5) description gives the  names  by  which
61       terminfo  knows a terminal, separated by “|” (pipe-bar) characters with
62       the last name field terminated by a comma.  The first name field is the
63       type's primary name, and is the one to use when setting TERM.  The last
64       name field (if distinct from the first) is actually  a  description  of
65       the  terminal  type  (it  may contain blanks; the others must be single
66       words).  Name fields between  the  first  and  last  (if  present)  are
67       aliases for the terminal, usually historical names retained for compat‐
68       ibility.
70       There are some conventions for how to  choose  terminal  primary  names
71       that  help  keep  them  informative and unique.  Here is a step-by-step
72       guide to naming terminals that also explains how to parse them:
74       First, choose a root name.  The root will consist of a lower-case  let‐
75       ter  followed by up to seven lower-case letters or digits.  You need to
76       avoid using punctuation characters in root names, because they are used
77       and  interpreted  as filenames and shell meta-characters (such as !, $,
78       *, ?, etc.) embedded in them may cause odd and unhelpful behavior.  The
79       slash  (/),  or any other character that may be interpreted by anyone's
80       file system (\, $, [, ]), is especially dangerous  (terminfo  is  plat‐
81       form-independent,  and  choosing  names  with  special characters could
82       someday make life difficult for users of a future port).  The  dot  (.)
83       character  is  relatively safe as long as there is at most one per root
84       name; some historical terminfo names use it.
86       The root name for a terminal or workstation console type should  almost
87       always  begin  with a vendor prefix (such as hp for Hewlett-Packard, wy
88       for Wyse, or att for AT&T terminals), or a common name of the  terminal
89       line  (vt  for  the  VT  series  of  terminals from DEC, or sun for Sun
90       Microsystems workstation  consoles,  or  regent  for  the  ADDS  Regent
91       series.   You  can  list  the  terminfo  tree  to see what prefixes are
92       already in common use.  The root name prefix should  be  followed  when
93       appropriate by a model number; thus vt100, hp2621, wy50.
95       The  root  name for a PC-Unix console type should be the OS name, i.e.,
96       linux, bsdos, freebsd, netbsd.  It should not be console or  any  other
97       generic that might cause confusion in a multi-platform environment!  If
98       a model number follows, it should indicate either the OS release  level
99       or the console driver release level.
101       The  root name for a terminal emulator (assuming it does not fit one of
102       the standard ANSI or vt100 types) should be the program name or a read‐
103       ily recognizable abbreviation of it (i.e., versaterm, ctrm).
105       Following  the  root name, you may add any reasonable number of hyphen-
106       separated feature suffixes.
108       2p   Has two pages of memory.  Likewise 4p, 8p, etc.
110       mc   Magic-cookie.  Some terminals (notably older Wyses) can only  sup‐
111            port one attribute without magic-cookie lossage.  Their base entry
112            is usually paired with another that has this suffix and uses magic
113            cookies to support multiple attributes.
115       -am  Enable auto-margin (right-margin wraparound).
117       -m   Mono mode - suppress color support.
119       -na  No  arrow  keys  -  termcap  ignores arrow keys which are actually
120            there on the terminal, so the user can use the arrow keys locally.
122       -nam No auto-margin - suppress am capability.
124       -nl  No labels - suppress soft labels.
126       -nsl No status line - suppress status line.
128       -pp  Has a printer port which is used.
130       -rv  Terminal in reverse video mode (black on white).
132       -s   Enable status line.
134       -vb  Use visible bell (flash) rather than beep.
136       -w   Wide; terminal is in 132 column mode.
138       Conventionally, if your terminal type is a variant intended to  specify
139       a  line  height,  that  suffix should go first.  So, for a hypothetical
140       FuBarCo model 2317 terminal in 30-line mode with  reverse  video,  best
141       form would be fubar-30-rv (rather than, say, “fubar-rv-30”).
143       Terminal  types  that are written not as standalone entries, but rather
144       as components to be plugged into other entries  via  use  capabilities,
145       are distinguished by using embedded plus signs rather than dashes.
147       Commands which use a terminal type to control display often accept a -T
148       option that accepts a terminal name  argument.   Such  programs  should
149       fall  back on the TERM environment variable when no -T option is speci‐
150       fied.


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


157       /usr/share/terminfo/?/*
158            compiled terminal capability data base
160       /etc/inittab
161            tty line initialization (AT&T-like UNIXes)
163       /etc/ttys
164            tty line initialization (BSD-like UNIXes)


167       curses(3X), terminfo(5), term(5).
171                                                                       term(7)