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NAME | DESCRIPTION | PORTABILITY | FILES | SEE ALSO | COLOPHON |
term(7) Miscellaneous Information Manual term(7)
term - conventions for naming terminal types
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
consoles.
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
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 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 @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@(1M) command. 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 @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 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
letter 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 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 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
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.
For maximum compatibility with older System V UNIXes, names and
aliases should be unique within the first 14 characters.
@TERMINFO@/?/*
compiled terminal capability data base
/etc/inittab
tty line initialization (AT&T-like UNIXes)
/etc/ttys
tty line initialization (BSD-like UNIXes)
curses(3X), terminfo(5), term(5).
This page is part of the ncurses (new curses) project. Information
about the project can be found at
⟨https://www.gnu.org/software/ncurses/ncurses.html⟩. If you have a
bug report for this manual page, send it to
bug-ncurses-request@gnu.org. This page was obtained from the
project's upstream Git mirror of the CVS repository
⟨git://ncurses.scripts.mit.edu/ncurses.git⟩ on 2017-07-05. If you
discover any rendering problems in this HTML version of the page, or
you believe there is a better or more up-to-date source for the page,
or you have corrections or improvements to the information in this
COLOPHON (which is not part of the original manual page), send a mail
to man-pages@man7.org
term(7)
Pages that refer to this page: pg(1), terminfo(5)