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 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 /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 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.

PORTABILITY

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

FILES

       /etc/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

       ncurses(3NCURSES), terminfo(5), term(5).

                                                                                                         term(7)