term(7) — Linux manual page


term(7)               Miscellaneous Information Manual               term(7)

NAME         top

       term - conventions for naming terminal types

DESCRIPTION         top

       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

       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

       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

       -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,

       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         top

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

FILES         top

            compiled terminal capability data base

            tty line initialization (AT&T-like UNIXes)

            tty line initialization (BSD-like UNIXes)

SEE ALSO         top

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

COLOPHON         top

       This page is part of the ncurses (new curses) project.  Information
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       ⟨https://www.gnu.org/software/ncurses/ncurses.html⟩.  If you have a
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       ⟨git://ncurses.scripts.mit.edu/ncurses.git⟩ on 2020-11-01.  (At that
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