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termcap(F)


termcap -- terminal capability database

Description

The file /etc/termcap is a database describing terminals. This database is used by packages such as vi, Lyrix[®], Multiplan[(TM)], and sub-routine packages such as curses(S). Terminals are described in termcap by giving a set of capabilities and by describing how operations are performed. Padding requirements and initialization sequences are included in termcap.

Entries in termcap consist of a number of fields separated by colons (:). The first entry for each terminal gives the names that are known for the terminal, separated by vertical bars (|). For compatibility with older systems the first name is always 2 characters long. The second name given is the most common abbreviation for the terminal and the name used by vi and ex. The last name given should be a long name fully identifying the terminal. Only the last name can contain blanks for readability.

Capabilities

The following is a list of the capabilities that can be defined for a given terminal. In this list, (P) indicates that padding can be specified, and (P*) indicates that padding can be based on the number of lines affected. The capability type and padding fields are described in detail in ``Types of capabilities''.

XENIX extension codes are described in ``XENIX extensions''.

Name Type Pad? Description
ae str (P) End alternate character set
al str (P*) Add new blank line
am bool   Terminal has automatic margins
as str (P) Start alternate character set
bc str   Backspace if not ^H
bs bool   Terminal can backspace with ^H
bt str (P) Back tab
bw bool   Backspace wraps from column 0 to last column
CC str   Command character in prototype if terminal settable
cd str (P*) Clear to end of display
ce str (P) Clear to end of line
ch str (P) Like cm but horizontal motion only, line stays same
cl str (P*) Clear screen
cm str (P) Cursor motion
co num   Number of columns in a line
cr str (P*) Carriage return, (default ^M)
cs str (P) Change scrolling region (vt100), like cm
cv str (P) Like ch but vertical only.
CW str   Sent by CHANGE WINDOW key
da bool   Display may be retained above
db bool   Display may be retained below
dB num   Number of millisec of bs delay needed
dC num   Number of millisec of cr delay needed
dc str (P*) Delete character
dF num   Number of millisec of ff delay needed
dl str (P*) Delete line
dm str   Delete mode (enter)
dN num   Number of millisec of nl delay needed
do str   Down one line
dT num   Number of millisec of tab delay needed
ed str   End delete mode
ei str   End insert mode; give ``:ei=:'' if ic
eo bool   Can erase overstrikes with a blank
ff str (P*) Hardcopy terminal page eject (default ^L)

 +-----+------+------+-----------------------------------------------------+
 |Name | Type | Pad? | Description                                         |
 +-----+------+------+-----------------------------------------------------+
 |ae   | str  | (P)  | End alternate character set                         |
 +-----+------+------+-----------------------------------------------------+
 |al   | str  | (P*) | Add new blank line                                  |
 +-----+------+------+-----------------------------------------------------+
 |am   | bool |      | Terminal has automatic margins                      |
 +-----+------+------+-----------------------------------------------------+
 |as   | str  | (P)  | Start alternate character set                       |
 +-----+------+------+-----------------------------------------------------+
 |bc   | str  |      | Backspace if not ^H                                 |
 +-----+------+------+-----------------------------------------------------+
 |bs   | bool |      | Terminal can backspace with ^H                      |
 +-----+------+------+-----------------------------------------------------+
 |bt   | str  | (P)  | Back tab                                            |
 +-----+------+------+-----------------------------------------------------+
 |bw   | bool |      | Backspace wraps from column 0 to last column        |
 +-----+------+------+-----------------------------------------------------+
 |CC   | str  |      | Command character in prototype if terminal settable |
 +-----+------+------+-----------------------------------------------------+
 |cd   | str  | (P*) | Clear to end of display                             |
 +-----+------+------+-----------------------------------------------------+
 |ce   | str  | (P)  | Clear to end of line                                |
 +-----+------+------+-----------------------------------------------------+
 |ch   | str  | (P)  | Like cm but horizontal motion only, line stays same |
 +-----+------+------+-----------------------------------------------------+
 |cl   | str  | (P*) | Clear screen                                        |
 +-----+------+------+-----------------------------------------------------+
 |cm   | str  | (P)  | Cursor motion                                       |
 +-----+------+------+-----------------------------------------------------+
 |co   | num  |      | Number of columns in a line                         |
 +-----+------+------+-----------------------------------------------------+
 |cr   | str  | (P*) | Carriage return, (default ^M)                       |
 +-----+------+------+-----------------------------------------------------+
 |cs   | str  | (P)  | Change scrolling region (vt100), like cm            |
 +-----+------+------+-----------------------------------------------------+
 |cv   | str  | (P)  | Like ch but vertical only.                          |
 +-----+------+------+-----------------------------------------------------+
 |CW   | str  |      | Sent by CHANGE WINDOW key                           |
 +-----+------+------+-----------------------------------------------------+
 |da   | bool |      | Display may be retained above                       |
 +-----+------+------+-----------------------------------------------------+
 |db   | bool |      | Display may be retained below                       |
 +-----+------+------+-----------------------------------------------------+
 |dB   | num  |      | Number of millisec of bs delay needed               |
 +-----+------+------+-----------------------------------------------------+
 |dC   | num  |      | Number of millisec of cr delay needed               |
 +-----+------+------+-----------------------------------------------------+
 |dc   | str  | (P*) | Delete character                                    |
 +-----+------+------+-----------------------------------------------------+
 |dF   | num  |      | Number of millisec of ff delay needed               |
 +-----+------+------+-----------------------------------------------------+
 |dl   | str  | (P*) | Delete line                                         |
 +-----+------+------+-----------------------------------------------------+
 |dm   | str  |      | Delete mode (enter)                                 |
 +-----+------+------+-----------------------------------------------------+
 |dN   | num  |      | Number of millisec of nl delay needed               |
 +-----+------+------+-----------------------------------------------------+
 |do   | str  |      | Down one line                                       |
 +-----+------+------+-----------------------------------------------------+
 |dT   | num  |      | Number of millisec of tab delay needed              |
 +-----+------+------+-----------------------------------------------------+
 |ed   | str  |      | End delete mode                                     |
 +-----+------+------+-----------------------------------------------------+
 |ei   | str  |      | End insert mode; give ``:ei=:'' if ic               |
 +-----+------+------+-----------------------------------------------------+
 |eo   | bool |      | Can erase overstrikes with a blank                  |
 +-----+------+------+-----------------------------------------------------+
 |ff   | str  | (P*) | Hardcopy terminal page eject (default ^L)           |
 +-----+------+------+-----------------------------------------------------+

hc bool   Hardcopy terminal
hd str   Half-line down (forward ½ linefeed)
ho str   Home cursor (if no cm)
hu str   Half-line up (reverse ½ linefeed)
hz str   Hazeltine; can't print ~'s
ic str (P) Insert character
if str   Name of file containing is
im str   Insert mode (enter); give ``:im='' if ic
in bool   Insert mode distinguishes nulls on display
ip str (P*) Insert pad after character inserted
is str   Terminal initialization string
k0-k9 str   Sent by ``other'' function keys 0-9
kb str   Sent by backspace key
kd str   Sent by terminal down arrow key
ke str   Out of ``keypad transmit'' mode
kh str   Sent by home key
kl str   Sent by terminal left arrow key
kn num   Number of ``other'' keys
ko str   Termcap entries for other non-function keys
kr str   Sent by terminal right arrow key
ks str   Put terminal in ``keypad transmit'' mode
ku str   Sent by terminal up arrow key
l0-l9 str   Labels on ``other'' function keys
LD str   Sent by line delete key
LF str   Sent by line feed key
li num   Number of lines on screen or page
ll str   Last line, first column (if no cm)
ma str   Arrow key map, used by vi version 2 only
mb bool   Blinking on
me bool   Turn off all attributes

 +------+------+------+---------------------------------------------+
 |hc    | bool |      | Hardcopy terminal                           |
 +------+------+------+---------------------------------------------+
 |hd    | str  |      | Half-line down (forward  linefeed)         |
 +------+------+------+---------------------------------------------+
 |ho    | str  |      | Home cursor (if no cm)                      |
 +------+------+------+---------------------------------------------+
 |hu    | str  |      | Half-line up (reverse  linefeed)           |
 +------+------+------+---------------------------------------------+
 |hz    | str  |      | Hazeltine; can't print ~'s                  |
 +------+------+------+---------------------------------------------+
 |ic    | str  | (P)  | Insert character                            |
 +------+------+------+---------------------------------------------+
 |if    | str  |      | Name of file containing is                  |
 +------+------+------+---------------------------------------------+
 |im    | str  |      | Insert mode (enter); give ``:im='' if ic    |
 +------+------+------+---------------------------------------------+
 |in    | bool |      | Insert mode distinguishes nulls on display  |
 +------+------+------+---------------------------------------------+
 |ip    | str  | (P*) | Insert pad after character inserted         |
 +------+------+------+---------------------------------------------+
 |is    | str  |      | Terminal initialization string              |
 +------+------+------+---------------------------------------------+
 |k0-k9 | str  |      | Sent by ``other'' function keys 0-9         |
 +------+------+------+---------------------------------------------+
 |kb    | str  |      | Sent by backspace key                       |
 +------+------+------+---------------------------------------------+
 |kd    | str  |      | Sent by terminal down arrow key             |
 +------+------+------+---------------------------------------------+
 |ke    | str  |      | Out of ``keypad transmit'' mode             |
 +------+------+------+---------------------------------------------+
 |kh    | str  |      | Sent by home key                            |
 +------+------+------+---------------------------------------------+
 |kl    | str  |      | Sent by terminal left arrow key             |
 +------+------+------+---------------------------------------------+
 |kn    | num  |      | Number of ``other'' keys                    |
 +------+------+------+---------------------------------------------+
 |ko    | str  |      | Termcap entries for other non-function keys |
 +------+------+------+---------------------------------------------+
 |kr    | str  |      | Sent by terminal right arrow key            |
 +------+------+------+---------------------------------------------+
 |ks    | str  |      | Put terminal in ``keypad transmit'' mode    |
 +------+------+------+---------------------------------------------+
 |ku    | str  |      | Sent by terminal up arrow key               |
 +------+------+------+---------------------------------------------+
 |l0-l9 | str  |      | Labels on ``other'' function keys           |
 +------+------+------+---------------------------------------------+
 |LD    | str  |      | Sent by line delete key                     |
 +------+------+------+---------------------------------------------+
 |LF    | str  |      | Sent by line feed key                       |
 +------+------+------+---------------------------------------------+
 |li    | num  |      | Number of lines on screen or page           |
 +------+------+------+---------------------------------------------+
 |ll    | str  |      | Last line, first column (if no cm)          |
 +------+------+------+---------------------------------------------+
 |ma    | str  |      | Arrow key map, used by vi version 2 only    |
 +------+------+------+---------------------------------------------+
 |mb    | bool |      | Blinking on                                 |
 +------+------+------+---------------------------------------------+
 |me    | bool |      | Turn off all attributes                     |
 +------+------+------+---------------------------------------------+

mi bool   Safe to move while in insert mode
ml str   Memory lock on above cursor
MR str   Set soft right margin
ms bool   Will scroll in stand-out mode
mu str   Memory unlock (turn off memory lock)
nc bool   No correctly working carriage return (DM2500,H2000)
nd str   Non-destructive space (cursor right)
nl str (P*) Newline character (default \n)
ns bool   Terminal is a CRT but doesn't scroll
os bool   Terminal overstrikes
pc str   Pad character (rather than null)
PN str   Start local printing
PS str   End local printing
pt bool   Has hardware tabs (may need to be set with is)
PU str   Select pulse dialing
RC str   Remove time-of-day clock
se str   End stand out mode
sf str (P) Scroll forwards
sg num   Number of blank chars left by so or se
so str   Begin stand out mode
sr str (P) Scroll reverse (backwards)
ta str (P) Tab (other than ^I or with padding)
tc str   Entry of similar terminal - must be last
te str   String to end programs that use cm
ti str   String to begin programs that use cm
TO str   Select tone dialing
uc str   Underscore one char and move past it
ue str   End underscore mode
ug num   Number of blank chars left by us or ue
ul bool   Terminal underlines but doesn't overstrike
up str   Upline (cursor up)
UP str   Move cursor up one line
us str   Start underscore mode
vb str   Visible bell (may not move cursor)
ve str   Sequence to end open/visual mode
vs str   Sequence to start open/visual mode
xb bool   Beehive (f1=escape, f2=ctrl C)
xn bool   A newline is ignored after a wrap (Concept)
xr bool   Return acts like ce \r \n (Delta Data)
xs bool   Standard out not erased by writing over it (HP 264)
xt bool   Tabs are destructive, magic so char (Teleray 1061)

 +---+------+------+-----------------------------------------------------+
 |mi | bool |      | Safe to move while in insert mode                   |
 +---+------+------+-----------------------------------------------------+
 |ml | str  |      | Memory lock on above cursor                         |
 +---+------+------+-----------------------------------------------------+
 |MR | str  |      | Set soft right margin                               |
 +---+------+------+-----------------------------------------------------+
 |ms | bool |      | Will scroll in stand-out mode                       |
 +---+------+------+-----------------------------------------------------+
 |mu | str  |      | Memory unlock (turn off memory lock)                |
 +---+------+------+-----------------------------------------------------+
 |nc | bool |      | No correctly working carriage return (DM2500,H2000) |
 +---+------+------+-----------------------------------------------------+
 |nd | str  |      | Non-destructive space (cursor right)                |
 +---+------+------+-----------------------------------------------------+
 |nl | str  | (P*) | Newline character (default \n)                      |
 +---+------+------+-----------------------------------------------------+
 |ns | bool |      | Terminal is a CRT but doesn't scroll                |
 +---+------+------+-----------------------------------------------------+
 |os | bool |      | Terminal overstrikes                                |
 +---+------+------+-----------------------------------------------------+
 |pc | str  |      | Pad character (rather than null)                    |
 +---+------+------+-----------------------------------------------------+
 |PN | str  |      | Start local printing                                |
 +---+------+------+-----------------------------------------------------+
 |PS | str  |      | End local printing                                  |
 +---+------+------+-----------------------------------------------------+
 |pt | bool |      | Has hardware tabs (may need to be set with is)      |
 +---+------+------+-----------------------------------------------------+
 |PU | str  |      | Select pulse dialing                                |
 +---+------+------+-----------------------------------------------------+
 |RC | str  |      | Remove time-of-day clock                            |
 +---+------+------+-----------------------------------------------------+
 |se | str  |      | End stand out mode                                  |
 +---+------+------+-----------------------------------------------------+
 |sf | str  | (P)  | Scroll forwards                                     |
 +---+------+------+-----------------------------------------------------+
 |sg | num  |      | Number of blank chars left by so or se              |
 +---+------+------+-----------------------------------------------------+
 |so | str  |      | Begin stand out mode                                |
 +---+------+------+-----------------------------------------------------+
 |sr | str  | (P)  | Scroll reverse (backwards)                          |
 +---+------+------+-----------------------------------------------------+
 |ta | str  | (P)  | Tab (other than ^I or with padding)                 |
 +---+------+------+-----------------------------------------------------+
 |tc | str  |      | Entry of similar terminal - must be last            |
 +---+------+------+-----------------------------------------------------+
 |te | str  |      | String to end programs that use cm                  |
 +---+------+------+-----------------------------------------------------+
 |ti | str  |      | String to begin programs that use cm                |
 +---+------+------+-----------------------------------------------------+
 |TO | str  |      | Select tone dialing                                 |
 +---+------+------+-----------------------------------------------------+
 |uc | str  |      | Underscore one char and move past it                |
 +---+------+------+-----------------------------------------------------+
 |ue | str  |      | End underscore mode                                 |
 +---+------+------+-----------------------------------------------------+
 |ug | num  |      | Number of blank chars left by us or ue              |
 +---+------+------+-----------------------------------------------------+
 |ul | bool |      | Terminal underlines but doesn't overstrike          |
 +---+------+------+-----------------------------------------------------+
 |up | str  |      | Upline (cursor up)                                  |
 +---+------+------+-----------------------------------------------------+
 |UP | str  |      | Move cursor up one line                             |
 +---+------+------+-----------------------------------------------------+
 |us | str  |      | Start underscore mode                               |
 +---+------+------+-----------------------------------------------------+
 |vb | str  |      | Visible bell (may not move cursor)                  |
 +---+------+------+-----------------------------------------------------+
 |ve | str  |      | Sequence to end open/visual mode                    |
 +---+------+------+-----------------------------------------------------+
 |vs | str  |      | Sequence to start open/visual mode                  |
 +---+------+------+-----------------------------------------------------+
 |xb | bool |      | Beehive (f1=escape, f2=ctrl C)                      |
 +---+------+------+-----------------------------------------------------+
 |xn | bool |      | A newline is ignored after a wrap (Concept)         |
 +---+------+------+-----------------------------------------------------+
 |xr | bool |      | Return acts like ce \r \n (Delta Data)              |
 +---+------+------+-----------------------------------------------------+
 |xs | bool |      | Standard out not erased by writing over it (HP 264) |
 +---+------+------+-----------------------------------------------------+
 |xt | bool |      | Tabs are destructive, magic so char (Teleray 1061)  |
 +---+------+------+-----------------------------------------------------+

A sample entry

The following entry describes the Concept-100, and is among the more complex entries in the termcap file. (This particular Concept entry is outdated, and is used as an example only.)
c1c100concept100:is=\EU\Ef\E7\E5\E8\El\ENH\EK\E\200\Eo&\200:\
	:al=3*\E^R:am:bs:cd=16*\E^C:ce=16\E^S:cl=2*^L:\
	:cm=\Ea%+ %+ :co#80:dc=16\E^A:dl=3*\E^B:\
	:ei=\E\200:eo:im=\E^P:in:ip=16*:li#24:mi:nd=\E=:\
	:se=\Ed\Ee:so=\ED\EE:ta=8\t:ul:up=\E;:vb=\Ek\EK:xn:
Entries may continue over to multiple lines by giving a backslash (\) as the last character of a line. Empty fields can be included for readability between the last field on a line and the first field on the next. Capabilities in termcap are of three types: Boolean capabilities, which indicate that the terminal has some particular feature, numeric capabilities giving the size of the terminal or the size of particular delays, and string capabilities, which give a sequence that can be used to perform particular terminal operations.

Types of capabilities

All capabilities have two letter codes. For instance, the fact that the Concept has ``automatic margins'' (i.e., an automatic return and linefeed when the end of a line is reached) is indicated by the capability am. The description of the Concept includes am. Numeric capabilities are followed by the character ``#'' and then the value. Thus co, which indicates the number of columns the terminal has, gives the value ``80'' for the Concept.

Finally, string valued capabilities, such as ce (clear to end of line sequence) are given by the two character code, an ``='', and then a string ending at the next following ``:''. A delay in milliseconds may appear after the ``='' in such a capability, and padding characters are supplied by the editor after the rest of the string is sent to provide this delay. The delay can be either an integer, for example, ``20'', or an integer followed by an ``*'', such as ``3*''. A ``*'' indicates that the padding required is proportional to the number of lines affected by the operation, and the amount given is the per-affected-unit padding required. When a ``*'' is specified, it is sometimes useful to give a delay of the form ``3.5'' to specify a delay per unit to tenths of milliseconds.

A number of escape sequences are provided in the string valued capabilities for easy encoding of characters there. A \E maps to an ESCAPE character, ^x maps to a Control x for any appropriate x, and the sequences \n, \r, \t, \b, \f give a Newline, Return, Tab, Backspace and Formfeed. Finally, characters may be given as three octal digits after a ``\'', and the characters ``^'' and ``\'' may be given as ``\^'' and ``\\''. If it is necessary to place a colon (:) in a capability, it must be escaped in octal as \072. If it is necessary to place a null character in a string capability, it must be encoded as \200. The routines that deal with termcap use C strings, and strip the high bits of the output very late so that a \200 comes out as a \000 would.

Preparing descriptions

The most effective way to prepare a terminal description is by imitating the description of a similar terminal in termcap and building up a description gradually, using partial descriptions with ex to check that they are correct. Be aware that a very unusual terminal may expose deficiencies in the ability of the termcap file to describe it. To test a new terminal description, you can set the environment variable TERMCAP to a pathname of a file containing the description you are working on and the editor will look there rather than in /etc/termcap. TERMCAP can also be set to the termcap entry itself to avoid reading the file when starting up the editor.

Basic capabilities

The number of columns on each line for the terminal is given by the co numeric capability. If the terminal is a CRT, the number of lines on the screen is given by the li capability. If the terminal wraps around to the beginning of the next line when it reaches the right margin, it should have the am capability. If the terminal can clear its screen, this is given by the cl string capability. If the terminal can backspace, it should have the bs capability, unless a backspace is accomplished by a character other than ^H in which case you should give this character as the bc string capability. If it overstrikes (rather than clearing a position when a character is struck over), it should have the os capability.

A very important point here is that the local cursor motions encoded in termcap are undefined at the left and top edges of a CRT terminal. The editor will never attempt to backspace around the left edge, nor will it attempt to go up locally off the top. The editor assumes that feeding off the bottom of the screen will cause the screen to scroll up, and the am capability tells whether the cursor sticks at the right edge of the screen. If the terminal has switch selectable automatic margins, the termcap file usually assumes that this is on (that is, am).

These capabilities suffice to describe hardcopy and ``glass-tty'' terminals. Thus the Model 33 Teletype is described as:

   t333tty33:co#72:os
while the Lear Siegler ADM-3 is described as:
   cladm3|3|lsi adm3:am:bs:cl=^Z:li#24:co#80

Cursor addressing

Cursor addressing in the terminal is described by a cm string capability. This capability uses printf(S)-like escapes (such as %x) in it. These substitute to encodings of the current line or column position, while other characters are passed through unchanged. If the cm string is thought of as being a function, its arguments are the line and then the column to which motion is desired, and the ``%'' encodings have the following meanings:

%d replaced by line/column position, 0 origin
%2 like %2d - 2 digit field
%3 like %3d - 3 digit field
%. like printf(S) %c
%+x adds x to value, then %.
%>xy if value > x adds y, no output
%r reverses order of line and column, no output
%i increments line/column position (for 1 origin)
%% gives a single %
%n exclusive or row and column with 0140 (DM2500)
%B BCD (16*(x/10)) + (x%10), no output
%D Reverse coding (x-2*(x%16)), no output (Delta Data).

Consider the HP2645, which, to get to row 3 and column 12, needs to be sent \E&a12c03Y padded for 6 milliseconds. Note that the order of the rows and columns is inverted here, and that the row and column are printed as two digits. Thus its cm capability is ``cm=6\E&%r%2c%2Y''. The Microterm ACT-IV needs the current row and column sent preceded by a ^T, with the row and column simply encoded in binary, ``cm=^T%.%.''. Terminals that use ``%.'' need to be able to backspace the cursor (bs or bc), and to move the cursor up one line on the screen (up introduced ``Cursor motions''). This is necessary because it is not always safe to transmit \t, \n ^D and \r, as the system may change or discard them. A final example is the LSI ADM-3a, which uses row and column offset by a blank character, thus ``cm=\E=%+ %+''.

Cursor motions

If the terminal can move the cursor one position to the right, leaving the character at the current position unchanged, this sequence should be given as nd (non-destructive space). If it can move the cursor up a line on the screen in the same column, it should be given as up.

If the terminal has no cursor addressing capability, but can home the cursor (to very upper left corner of screen), this can be given as ho; similarly, a fast way of getting to the lower left hand corner can be given as ll; this may involve going up with up from the home position, but the editor will never do this itself (unless ll does) because it makes no assumption about the effect of moving up from the home position.

Area clears

If the terminal can clear from the current position to the end of the line, leaving the cursor where it is, the sequence should be given as ce. If the terminal can clear from the current position to the end of the display, the sequence should be given as cd. The editor only uses cd from the first column of a line.

Insert/delete line

If the terminal can open a new blank line before the line where the cursor is, the sequence should be given as al. Note that this is done only from the first position of a line. The cursor must then appear on the newly blank line. If the terminal can delete the line on which the cursor rests, the sequence should be given as dl. This is done only from the first position on the line to be deleted. If the terminal can scroll the screen backwards, the sequence can be given as sb, but al can suffice. If the terminal can retain display memory above, the da capability should be given, and if display memory can be retained below, then db should be given. These let the editor know that deleting a line on the screen may bring non-blank lines up from below, or that scrolling back with sb may bring down non-blank lines.

Insert/delete character

termcap has two ways of describing how intelligent terminals handle insert/delete character operations. The most common insert/delete character operations affect only the characters on the current line and shift characters off the end of the line. Other terminals, such as the Concept 100 and the Perkin Elmer Owl, make a distinction between typed and untyped blanks on the screen, shifting upon an insert or delete only to an untyped blank on the screen which is either eliminated, or expanded to two untyped blanks. You can find out which kind of terminal you have by clearing the screen and entering text separated by cursor motions. Enter ``abc    def'', using local cursor motions (not spaces) between the ``abc'' and the ``def''. Then position the cursor before the ``abc'' and put the terminal in insert mode. If entering characters causes the rest of the line to shift rigidly and characters to fall off the end, your terminal does not distinguish between blanks and untyped positions. If the ``abc'' shifts over to the ``def'' which then move together around the end of the current line and onto the next as you insert, you have the second type of terminal, and should give the capability in, which stands for ``insert null''. No known terminals have an insert mode, not falling into one of these two classes.

The editor can handle both terminals that have an insert mode and terminals that send a simple sequence to open a blank position on the current line. Specify im as the sequence to get into insert mode, or give it an empty value if your terminal uses a sequence to insert a blank position. Specify ei as the sequence to leave insert mode (specify this with an empty value if you also gave im an empty value). Now specify ic as any sequence needed to be sent just before sending the character to be inserted. Most terminals with a true insert mode will not support ic, terminals that send a sequence to open a screen position should give it here. (Insert mode is preferable to the sequence to open a position on the screen if your terminal has both.) If post insert padding is needed, give this as a number of milliseconds in ip (a string option). Any other sequence that may need to be sent after an insert of a single character may also be given in ip.

It is occasionally necessary to move around while in insert mode to delete characters on the same line (for example, if there is a tab after the insertion position). If your terminal allows motion while in insert mode, you can give the capability mi to speed up inserting in this case. Omitting mi will affect only speed. Some terminals (notably Datamedia's) must not have mi because of the way their insert mode works.

Finally, you can specify delete mode by giving dm and ed to enter and exit delete mode, and dc to delete a single character while in delete mode.

Highlighting, underlining, and visible bells

If your terminal has sequences to enter and exit standout mode, these can be given as so and se respectively. If there are several flavors of standout mode (such as reverse video, blinking, or underlining - half bright is not usually an acceptable standout mode unless the terminal is in reverse video mode constantly), the preferred mode is reverse video by itself. It is acceptable, if the code to change into or out of standout mode leaves one, or even two blank spaces on the screen, as the TVI 912 and Teleray 1061 do. Although it may confuse some programs slightly, it cannot be helped.

Codes to begin and end underlining can be given as us and ue respectively. If the terminal has a code to underline the current character and move the cursor one space to the right, such as the Microterm Mime, the sequence can be given as uc. (If the underline code does not move the cursor to the right, specify the code followed by a nondestructive space.)

If the terminal has a way of flashing the screen to indicate an error silently (a bell replacement), the sequence can be given as vb; it must not move the cursor. If the terminal should be placed in a different mode during open and visual modes of ex, the sequence can be given as vs and ve, sent at the start and end of these modes respectively. These can be used to change from a underline to a block cursor and back.

If the terminal needs to be in a special mode when running a program that addresses the cursor, the codes to enter and exit this mode can be given as ti and te. This arises, for example, from terminals like the Concept with more than one page of memory. If the terminal has only memory relative cursor addressing and not screen relative cursor addressing, a one screen-sized window must be fixed into the terminal for cursor addressing to work properly.

If your terminal correctly generates underlined characters (with no special codes needed), even though it does not overstrike, you should give the capability ul. If overstrikes are erasable with a blank, this should be indicated by specifying eo.

Keypad

If the terminal has a keypad that transmits codes when the keys are pressed, this information can be given. Note that it is not possible to handle terminals where the keypad only works in local (this applies, for example, to the unshifted HP 2621 keys). If the keypad can be set to transmit or not to transmit, enter these codes as ks and ke. Otherwise, the keypad is assumed always to transmit. The codes sent by the left arrow, right arrow, up arrow, down arrow, and home keys can be given as kl, kr, ku, kd, and kh. If there are function keys such as f0, f1, ..., f9, the codes they send can be given as k0, k1, ..., k9. If there are other keys that transmit the same code as the terminal expects for the corresponding function, such as clear screen, the termcap 2 letter codes can be given in the ko capability, for example, ``:ko=cl,ll,sf,sb:'', which says that the terminal has clear, home down, scroll down, and scroll up keys that transmit the same thing as the cl, ll, sf, and sb entries.

The ma entry is also used to indicate arrow keys on terminals which have single character arrow keys. It is obsolete, but still in use in version 2 of vi, which must be run on some minicomputers due to memory limitations. This field is redundant with kl, kr, ku, kd, and kh. It consists of groups of two characters. In each group, the first character is what an arrow key sends, the second character is the corresponding vi command. These commands are h for kl, j for kd, k for ku, l for kr, and H for kh. For example, the Mime would be :ma=^Kj^Zk^Xl: indicating arrow keys left (^H), down (^K), up (^Z), and right (^X). (There is no home key on the Mime.)

Miscellaneous

If the terminal requires other than a null (zero) character as a pad, this can be given as pc.

If tabs on the terminal require padding, or if the terminal uses a character other than ^I to tab, the sequence can be given as ta.

Terminals that do not allow ``~'' characters to be displayed (such as Hazeltines), should indicate hz. Datamedia terminals that echo carriage-return-linefeed for carriage return, and then ignore a following linefeed, should indicate nc. Early Concept terminals, that ignore a linefeed immediately after an am wrap, should indicate xn. If an erase-eol is required to get rid of standout (instead of merely writing on top of it), xs should be given. Teleray terminals, where tabs turn all characters moved over to blanks, should indicate xt. Other specific terminal problems may be corrected by adding more capabilities of the form xx.

If the leading character for commands to the terminal (normally the escape character) can be set by the software, specify the command character(s) with the capability CC.

Other capabilities include is, an initialization string for the terminal, and if, the name of a file containing long initialization strings. These strings are expected to properly clear and then set the tabs on the terminal, if the terminal has settable tabs. If both are given, is is displayed before if. This is useful where if is /usr/lib/tabset/std, but is clears the tabs first.

Similar terminals

If there are two very similar terminals, one can be defined as being just like the other with certain exceptions. The string capability, tc, can be given with the name of the similar terminal. This capability must be last and the combined length of the two entries must not exceed 2048. Since termlib routines search the entry from left to right, and since the tc capability is replaced by the corresponding entry, the capabilities given at the left override the ones in the similar terminal. A capability can be canceled with xx@ where xx is the capability.
For example:
   hn2621nl:ks@:ke@:tc=2621:
This defines a 2621nl that does not have the ks or ke capabilities, and does not turn on the function key labels when in visual mode. This is useful for different modes for a terminal, or for different user preferences.

XENIX extensions

This table lists XENIX extensions to the termcap capabilities. It shows which codes generate information input from the keyboard to the program reading the keyboard and which codes generate information output from the program to the screen. XENIX extension codes are additional to the standard entries and are used by several application programs. As with the standard entries, not all modes are supported by all applications or terminals. Some of these entries refer to specific terminal output capabilities (such as GS for ``graphics start''). Others describe character sequences sent by keys that appear on a keyboard. There are also entries that are used to attribute special meanings to other keys (or combinations of keys) for use in a particular software program. Some of the XENIX extension capabilities have a similar function to standard capabilities.

They are used to redefine specific keys (such as using function keys as arrow keys). The extension capabilities are included in the /etc/termcap file, as they are required for some utilities.

Name Type Pad? Description
CF str   Cursor off
CL str   Sent by Char Left key
CO str   Cursor on
DA bool   Delete attribute string
EN str   Sent by End key
G1 str   Upper-right (1st quadrant) corner character
G2 str   Upper-left (2nd quadrant) corner character
G3 str   Lower-left (3rd quadrant) corner character
G4 str   Lower-right (4th quadrant) corner character
G5 str   Upper right (1st quadrant) corner character (double)
G6 str   Upper left (2nd quadrant) corner character (double)
G7 str   Lower left (3rd quadrant) corner character (double)
G8 str   Lower right (4th quadrant) corner character (double)
GC str   Center graphics character (similar to +)
Gc str   Center graphics character (double)
GD str   Down-tick character
Gd str   Down tick character (double)
GE str   Graphics mode end
GG num   Number of chars taken by GS and GE
GH str   Horizontal bar character
Gh str   Horizontal bar character (double)
GL str   Left-tick character
Gl str   left-tick character (double)
GR str   Right-tick character
Gr str   right-tick character (double)
GS str   Graphics mode start
GU str   Up-tick character
Gu str   Up-tick character (double)
GV str   Vertical bar character
Gv str   Vertical bar character (double)
HM str   Sent by <Home> key (if not kh)
MP str   Multiplan initialization string
NU str   Sent by Next unlocked celL key
RF str   Sent by Toggle reference key
RT str   Sent by <Return> key
WL str   Sent by Word Left key
WR str   Sent by Word Right key

 +-----+------+------+------------------------------------------------------+
 |Name | Type | Pad? | Description                                          |
 +-----+------+------+------------------------------------------------------+
 |CF   | str  |      | Cursor off                                           |
 +-----+------+------+------------------------------------------------------+
 |CL   | str  |      | Sent by Char Left key                                |
 +-----+------+------+------------------------------------------------------+
 |CO   | str  |      | Cursor on                                            |
 +-----+------+------+------------------------------------------------------+
 |DA   | bool |      | Delete attribute string                              |
 +-----+------+------+------------------------------------------------------+
 |EN   | str  |      | Sent by End key                                      |
 +-----+------+------+------------------------------------------------------+
 |G1   | str  |      | Upper-right (1st quadrant) corner character          |
 +-----+------+------+------------------------------------------------------+
 |G2   | str  |      | Upper-left (2nd quadrant) corner character           |
 +-----+------+------+------------------------------------------------------+
 |G3   | str  |      | Lower-left (3rd quadrant) corner character           |
 +-----+------+------+------------------------------------------------------+
 |G4   | str  |      | Lower-right (4th quadrant) corner character          |
 +-----+------+------+------------------------------------------------------+
 |G5   | str  |      | Upper right (1st quadrant) corner character (double) |
 +-----+------+------+------------------------------------------------------+
 |G6   | str  |      | Upper left (2nd quadrant) corner character (double)  |
 +-----+------+------+------------------------------------------------------+
 |G7   | str  |      | Lower left (3rd quadrant) corner character (double)  |
 +-----+------+------+------------------------------------------------------+
 |G8   | str  |      | Lower right (4th quadrant) corner character (double) |
 +-----+------+------+------------------------------------------------------+
 |GC   | str  |      | Center graphics character (similar to +)             |
 +-----+------+------+------------------------------------------------------+
 |Gc   | str  |      | Center graphics character (double)                   |
 +-----+------+------+------------------------------------------------------+
 |GD   | str  |      | Down-tick character                                  |
 +-----+------+------+------------------------------------------------------+
 |Gd   | str  |      | Down tick character (double)                         |
 +-----+------+------+------------------------------------------------------+
 |GE   | str  |      | Graphics mode end                                    |
 +-----+------+------+------------------------------------------------------+
 |GG   | num  |      | Number of chars taken by GS and GE                   |
 +-----+------+------+------------------------------------------------------+
 |GH   | str  |      | Horizontal bar character                             |
 +-----+------+------+------------------------------------------------------+
 |Gh   | str  |      | Horizontal bar character (double)                    |
 +-----+------+------+------------------------------------------------------+
 |GL   | str  |      | Left-tick character                                  |
 +-----+------+------+------------------------------------------------------+
 |Gl   | str  |      | left-tick character (double)                         |
 +-----+------+------+------------------------------------------------------+
 |GR   | str  |      | Right-tick character                                 |
 +-----+------+------+------------------------------------------------------+
 |Gr   | str  |      | right-tick character (double)                        |
 +-----+------+------+------------------------------------------------------+
 |GS   | str  |      | Graphics mode start                                  |
 +-----+------+------+------------------------------------------------------+
 |GU   | str  |      | Up-tick character                                    |
 +-----+------+------+------------------------------------------------------+
 |Gu   | str  |      | Up-tick character (double)                           |
 +-----+------+------+------------------------------------------------------+
 |GV   | str  |      | Vertical bar character                               |
 +-----+------+------+------------------------------------------------------+
 |Gv   | str  |      | Vertical bar character (double)                      |
 +-----+------+------+------------------------------------------------------+
 |HM   | str  |      | Sent by Home key (if not kh)                         |
 +-----+------+------+------------------------------------------------------+
 |MP   | str  |      | Multiplan initialization string                      |
 +-----+------+------+------------------------------------------------------+
 |NU   | str  |      | Sent by Next unlocked celL key                       |
 +-----+------+------+------------------------------------------------------+
 |RF   | str  |      | Sent by Toggle reference key                         |
 +-----+------+------+------------------------------------------------------+
 |RT   | str  |      | Sent by Return key                                   |
 +-----+------+------+------------------------------------------------------+
 |WL   | str  |      | Sent by Word Left key                                |
 +-----+------+------+------------------------------------------------------+
 |WR   | str  |      | Sent by Word Right key                               |
 +-----+------+------+------------------------------------------------------+

Cursor motion

Some application programs make use of special editing codes. CR and CL move the cursor one character right and left respectively. WR and WL move the cursor one word right and left respectively. CW changes windows, when they are used in the program.

Some application programs turn off the cursor. This is accomplished using CF for cursor off and CO to turn it back on.

Graphic mode

If the terminal has graphics capabilities, this mode can be turned on and off with the GS and GE codes. Some terminals generate graphics characters from all keys when in graphics mode (such as the Visual 50). The other G codes specify particular graphics characters accessed by escape sequences. These characters are available on some terminals as alternate graphics character sets (not as a bit-map graphic mode). The vt100 has access to this kind of alternate graphics character set, but not to a bit-map graphic mode.

Limitations

ex allows only 256 characters for string capabilities, and the routines in termcap(S) do not check for overflow of this buffer. The total length of a single entry (excluding only escaped newlines) may not exceed 2048.

The ma, vs, and ve entries are specific to the vi program.

Not all programs support all entries. There are entries that are not supported by any program.

XENIX termcap extensions are explained in detail in the software application documentation.

Refer to the screen(HW) manual page, for a description of the character sequences used by the monitor device on your specific system.

Files

/etc/termcap file containing terminal descriptions

See also

ex(C), curses(S), more(C), screen(HW), termcap(S), tset(C), vi(C)

Standards conformance

termcap is not part of any currently supported standard; it was developed at the University of California at Berkeley and is used with permission.
© 2003 Caldera International, Inc. All rights reserved.
SCO OpenServer Release 5.0.7 -- 11 February 2003