man > term(7)

term(7)                                     Miscellaneous                                    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 Unices) or /etc/ttys (BSD Unices).  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 export‐
       ing  “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 deduc‐
       ing 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 incorporat‐
       ing  options (such as visual bell or reverse-video) which you wish to override the system de‐
       fault type for your line.

       Terminal type descriptions are stored as files of capability data  underneath  /etc/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 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 /etc/terminfo named for its first letter).  This command dumps a ca‐
       pability 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 termi‐
       nal, 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  in‐
       formative  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  espe‐
       cially  dangerous  (terminfo is platform-independent, and choosing names with special charac‐
       ters 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  suf‐
       fixes.

       2p   Has two pages of memory.  Likewise 4p, 8p, etc.

       mc   Magic-cookie.  Some terminals (notably older Wyses) can only support one attribute with‐
            out 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.

FILES
       /etc/terminfo
              compiled terminal description database

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

       /etc/ttys
              tty line initialization (BSD-like Unices)

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

SEE ALSO
       ncurses(3NCURSES), term(5), terminfo(5)

ncurses 6.4                                  2023-12-02                                      term(7)