.\" Copyright (c) 1980 Regents of the University of California.
.\" All rights reserved. The Berkeley software License Agreement
.\" specifies the terms and conditions for redistribution.
.\" @(#)termcap.5 6.6 (Berkeley) %G%
.TH TERMCAP 5 "1 November 1985"
termcap \- terminal capability data base
is a data base describing terminals,
Terminals are described in
by giving a set of capabilities that they have and by describing
how operations are performed.
Padding requirements and initialization sequences
consist of a number of `:'-separated fields.
The first entry for each terminal gives the names that are known for the
terminal, separated by `|' characters.
The first name is always two characters
long and is used by older systems which store the terminal type
in a 16-bit word in a system-wide data base.
The second name given is the most common abbreviation for the terminal,
the last name given should be a long name fully identifying the terminal,
and all others are understood as synonyms for the terminal name.
All names but the first and last
should be in lower case and contain no blanks;
the last name may well contain
upper case and blanks for readability.
Terminal names (except for the last, verbose entry)
should be chosen using the following conventions.
The particular piece of hardware making up the terminal
should have a root name chosen, thus \*(lqhp2621\*(rq.
This name should not contain hyphens.
Modes that the hardware can be in
should be indicated by appending a hyphen and an indicator of the mode.
Therefore, a \*(lqvt100\*(rq in 132-column mode would be \*(lqvt100-w\*(rq.
The following suffixes should be used where possible:
.ta \w'\fBSuffix\fP\ \ \ 'u +\w'With automatic margins (usually default)\ \ 'u
.nr Xx \n(.lu-\n(.i-\w'\fBSuffix\fP\ \ \ With automatic margins (usually default)\ \ vt100-am'u
\fBSuffix Meaning Example\fP
-w Wide mode (more than 80 columns) vt100-w
-am With automatic margins (usually default) vt100-am
-nam Without automatic margins vt100-nam
-\fIn\fP Number of lines on the screen aaa-60
-na No arrow keys (leave them in local) concept100-na
-\fIn\^\fPp Number of pages of memory concept100-4p
-rv Reverse video concept100-rv
field in the table have the following meanings
(more than one may apply to a capability):
N indicates numeric parameter(s)
P indicates that padding may be specified
* indicates that padding may be based on the number of lines affected
o indicates capability is obsolete
\*(lqObsolete\*(rq capabilities have no
since they were considered useless,
or are subsumed by other capabilities.
New software should not rely on them at all.
.ta \w'\fBName \fP'u +\w'\fBType \fP'u +\w'\fBNotes \fP'u
\fBName Type Notes Description\fP
ae str (P) End alternate character set
AL str (NP*) Add \fIn\^\fP new blank lines
al str (P*) Add new blank line
am bool Terminal has automatic margins
as str (P) Start alternate character set
bc str (o) Backspace if not \fB^H\fP
bl str (P) Audible signal (bell)
bs bool (o) Terminal can backspace with \fB^H\fP
bw bool \fBle\fP (backspace) wraps from column 0 to last column
CC str Terminal settable command character in prototype
cd str (P*) Clear to end of display
ce str (P) Clear to end of line
ch str (NP) Set cursor column (horizontal position)
cl str (P*) Clear screen and home cursor
CM str (NP) Memory-relative cursor addressing
cm str (NP) Screen-relative cursor motion
co num Number of columns in a line (See BUGS section below)
cr str (P) Carriage return
cs str (NP) Change scrolling region (VT100)
ct str (P) Clear all tab stops
cv str (NP) Set cursor row (vertical position)
da bool Display may be retained above the screen
dB num (o) Milliseconds of \fBbs\fP delay needed (default 0)
db bool Display may be retained below the screen
DC str (NP*) Delete \fIn\^\fP characters
dC num (o) Milliseconds of \fBcr\fP delay needed (default 0)
dc str (P*) Delete character
dF num (o) Milliseconds of \fBff\fP delay needed (default 0)
DL str (NP*) Delete \fIn\^\fP lines
dN num (o) Milliseconds of \fBnl\fP delay needed (default 0)
DO str (NP*) Move cursor down \fIn\^\fP lines
ds str Disable status line
dT num (o) Milliseconds of horizontal tab delay needed (default 0)
dV num (o) Milliseconds of vertical tab delay needed (default 0)
ec str (NP) Erase \fIn\^\fP characters
eo bool Can erase overstrikes with a blank
es bool Escape can be used on the status line
ff str (P*) Hardcopy terminal page eject
fs str Return from status line
gn bool Generic line type (\fIe.g.\fP dialup, switch)
hc bool Hardcopy terminal
hd str Half-line down (forward 1/2 linefeed)
hs bool Has extra \*(lqstatus line\*(rq
hu str Half-line up (reverse 1/2 linefeed)
hz bool Cannot print ~s (Hazeltine)
i1-i3 str Terminal initialization strings (\fIterminfo\^\fP only)
IC str (NP*) Insert \fIn\^\fP blank characters
ic str (P*) Insert character
if str Name of file containing initialization string
in bool Insert mode distinguishes nulls
iP str Pathname of program for initialization (\fIterminfo\^\fP only)
ip str (P*) Insert pad after character inserted
is str Terminal initialization string (\fItermcap\^\fP only)
it num Tabs initially every \fIn\^\fP positions
K1 str Sent by keypad upper left
K2 str Sent by keypad upper right
K3 str Sent by keypad center
K4 str Sent by keypad lower left
K5 str Sent by keypad lower right
k0-k9 str Sent by function keys 0-9
kA str Sent by insert-line key
ka str Sent by clear-all-tabs key
kb str Sent by backspace key
kC str Sent by clear-screen or erase key
kD str Sent by delete-character key
kd str Sent by down-arrow key
kE str Sent by clear-to-end-of-line key
ke str Out of \*(lqkeypad transmit\*(rq mode
kF str Sent by scroll-forward/down key
kH str Sent by home-down key
kI str Sent by insert-character or enter-insert-mode key
kL str Sent by delete-line key
kl str Sent by left-arrow key
kM str Sent by insert key while in insert mode
km bool Has a \*(lqmeta\*(rq key (shift, sets parity bit)
kN str Sent by next-page key
kn num (o) Number of function (\fBk0\fP\-\fBk9\fP) keys (default 0)
ko str (o) Termcap entries for other non-function keys
kP str Sent by previous-page key
kR str Sent by scroll-backward/up key
kr str Sent by right-arrow key
kS str Sent by clear-to-end-of-screen key
ks str Put terminal in \*(lqkeypad transmit\*(rq mode
kT str Sent by set-tab key
kt str Sent by clear-tab key
ku str Sent by up-arrow key
l0-l9 str Labels on function keys if not \*(lqf\fIn\^\fP\*(rq
LC bool (o) Lower-case only
LE str (NP) Move cursor left \fIn\^\fP positions
le str (P) Move cursor left one position
li num Number of lines on screen or page (See BUGS section below)
ll str Last line, first column
lm num Lines of memory if > \fBli\fP (0 means varies)
ma str (o) Arrow key map (used by \fIvi\^\fP version 2 only)
mb str Turn on blinking attribute
md str Turn on bold (extra bright) attribute
me str Turn off all attributes
mh str Turn on half-bright attribute
mi bool Safe to move while in insert mode
mk str Turn on blank attribute (characters invisible)
ml str (o) Memory lock on above cursor
mm str Turn on \*(lqmeta mode\*(rq (8th bit)
mo str Turn off \*(lqmeta mode\*(rq
mp str Turn on protected attribute
mr str Turn on reverse-video attibute
ms bool Safe to move in standout modes
mu str (o) Memory unlock (turn off memory lock)
nc bool (o) No correctly-working \fBcr\fP (Datamedia 2500, Hazeltine 2000)
nd str Non-destructive space (cursor right)
NL bool (o) \fB\\n\fP is newline, not line feed
nl str (o) Newline character if not \fB\\n\fP
ns bool (o) Terminal is a \s-1CRT\s0 but doesn't scroll
nw str (P) Newline (behaves like \fBcr\fP followed by \fBdo\fP)
os bool Terminal overstrikes
pb num Lowest baud where delays are required
pc str Pad character (default \s-2NUL\s0)
pf str Turn off the printer
pk str Program function key \fIn\^\fP to type string \fIs\fP (\fIterminfo\^\fP only)
pl str Program function key \fIn\^\fP to execute string \fIs\fP (\fIterminfo\^\fP only)
pO str (N) Turn on the printer for \fIn\^\fP bytes
po str Turn on the printer
ps str Print contents of the screen
pt bool (o) Has hardware tabs (may need to be set with \fBis\fP)
px str Program function key \fIn\^\fP to transmit string \fIs\fP (\fIterminfo\^\fP only)
r1-r3 str Reset terminal completely to sane modes (\fIterminfo\^\fP only)
rc str (P) Restore cursor to position of last \fBsc\fP
rf str Name of file containing reset codes
RI str (NP) Move cursor right \fIn\^\fP positions
rp str (NP*) Repeat character \fIc n\^\fP times
rs str Reset terminal completely to sane modes (\fItermcap\^\fP only)
sa str (NP) Define the video attributes
sc str (P) Save cursor position
SF str (NP*) Scroll forward \fIn\^\fP lines
sf str (P) Scroll text up
sg num Number of garbage chars left by \fBso\fP or \fBse\fP (default 0)
so str Begin standout mode
SR str (NP*) Scroll backward \fIn\^\fP lines
sr str (P) Scroll text down
st str Set a tab in all rows, current column
ta str (P) Tab to next 8-position hardware tab stop
tc str Entry of similar terminal \- must be last
te str String to end programs that use \fItermcap\fP
ti str String to begin programs that use \fItermcap\fP
ts str (N) Go to status line, column \fIn\^\fP
UC bool (o) Upper-case only
uc str Underscore one character and move past it
ue str End underscore mode
ug num Number of garbage chars left by \fBus\fP or \fBue\fP (default 0)
ul bool Underline character overstrikes
UP str (NP*) Move cursor up \fIn\^\fP lines
up str Upline (cursor up)
us str Start underscore mode
vb str Visible bell (must not move cursor)
ve str Make cursor appear normal (undo \fBvs\fP/\fBvi\fP)
vi str Make cursor invisible
vs str Make cursor very visible
vt num Virtual terminal number (not supported on all systems)
wi str (N) Set current window
ws num Number of columns in status line
xb bool Beehive (f1=\s-2ESC\s0, f2=^C)
xn bool Newline ignored after 80 cols (Concept)
xo bool Terminal uses xoff/xon (\s-2DC3\s0/\s-2DC1\s0) handshaking
xr bool (o) Return acts like \fBce cr nl\fP (Delta Data)
xs bool Standout not erased by overwriting (Hewlett-Packard)
xt bool Tabs ruin, magic \fBso\fP char (Teleray 1061)
xx bool (o) Tektronix 4025 insert-line
The following entry, which describes the Concept\-100, is among the more
ca\||\|concept100\||\|c100\||\|concept\||\|c104\||\|concept100-4p\||\|HDS Concept\-100:\e
:al=3*\eE^R:am:bl=^G:cd=16*\eE^C:ce=16\eE^U:cl=2*^L:cm=\eEa%+ %+ :\e
:co#80:.cr=9^M:db:dc=16\eE^A:dl=3*\eE^B:do=^J:ei=\eE\e200:eo:im=\eE^P:in:\e
:ip=16*:is=\eEU\eEf\eE7\eE5\eE8\eEl\eENH\eEK\eE\e200\eEo&\e200\eEo\e47\eE:k1=\eE5:\e
:k2=\eE6:k3=\eE7:kb=^h:kd=\eE<:ke=\eEx:kh=\eE?:kl=\eE>:kr=\eE=:ks=\eEX:\e
:ku=\eE;:le=^H:li#24:mb=\eEC:me=\eEN\e200:mh=\eEE:mi:mk=\eEH:mp=\eEI:\e
:mr=\eED:nd=\eE=:pb#9600:rp=0.2*\eEr%.%+ :se=\eEd\eEe:sf=^J:so=\eEE\eED:\e
:.ta=8\et:te=\eEv \e200\e200\e200\e200\e200\e200\eEp\er\en:\e
:ti=\eEU\eEv 8p\eEp\er:ue=\eEg:ul:up=\eE;:us=\eEG:\e
:vb=\eEk\e200\e200\e200\e200\e200\e200\e200\e200\e200\e200\e200\e200\e200\e200\eEK:\e
:ve=\eEw:vs=\eEW:vt#8:xn:\e
:bs:cr=^M:dC#9:dT#8:nl=^J:ta=^I:pt:
Entries may continue onto multiple lines by giving a \e as the last
character of a line, and empty fields
may be included for readability (here between the last field on a line
and the first field on the next).
Comments may be included on lines beginning with \*(lq#\*(rq.
are of three types: Boolean capabilities,
which indicate particular features that the terminal has;
giving the size of the display or the size of other attributes;
which give character sequences that can be used to perform particular
All capabilities have two-letter codes.
For instance, the fact that
an automatic return and linefeed
when the end of a line is reached) is indicated by the Boolean capability
Hence the description of the Concept includes
Numeric capabilities are followed by the character `#' then the value.
which indicates the number of columns the display has,
gives the value `80' for the Concept.
Finally, string-valued capabilities, such as
sequence) are given by the two-letter code, an `=', then a string
ending at the next following `:'.
A delay in milliseconds may appear after
the `=' in such a capability,
which causes padding characters to be supplied by
after the remainder of the string is sent to provide this delay.
The delay can be either a number,
`20', or a number followed by
An `*' indicates that the padding required is proportional
to the number of lines affected by the operation, and the amount given is
the per-affected-line padding required.
(In the case of insert-character,
the factor is still the number of
this is always 1 unless the terminal has
and the software uses it.)
When an `*' is specified, it is sometimes useful to give a delay of the form
`3.5' to specify a delay per line to tenths of milliseconds.
(Only one decimal place is allowed.)
A number of escape sequences are provided in the string-valued capabilities
for easy encoding of control characters there.
maps to a control-X for any appropriate X,
map to linefeed, return, tab, backspace, and formfeed, respectively.
Finally, characters may be given as three octal digits after a
If it is necessary to place a
in a capability it must be escaped in
If it is necessary to place a \s-2NUL\s0
character in a string capability it
(The routines that deal with
use C strings and strip the high bits of the output very late, so that
Sometimes individual capabilities must be commented out.
To do this, put a period before the capability name.
For example, see the first
.B Preparing Descriptions
We now outline how to prepare descriptions of terminals.
The most effective way to prepare a terminal description is by imitating
the description of a similar terminal in
and to build up a description gradually, using partial descriptions
to check that they are correct.
Be aware that a very unusual terminal may expose deficiencies in
To easily test a new terminal description you are working on
you can put it in your home directory in a file called
and programs will look there before looking in
You can also set the environment variable
to a list of absolute file pathnames (separated by spaces or colons),
one of which contains the description you are working on,
and programs will search them in the order listed, and nowhere else.
environment variable is usually set to the
to avoid reading files when starting up a program.
To get the padding for insert-line right
(if the terminal manufacturer did not document it),
at 9600 baud, delete roughly 16 lines from the middle of the screen,
then hit the `u' key several times quickly.
If the display messes up, more padding is usually needed.
A similar test can be used for insert-character.
The number of columns on each line of the display is given by the
If the display is a \s-1CRT\s0, then the
number of lines on the screen is given by the
If the display wraps around to the beginning of the next line when
the cursor reaches the right margin, then it should have the
If the terminal can clear its screen,
the code to do this is given by the
If the terminal overstrikes
(rather than clearing the position when a character is overwritten),
If the terminal is a printing terminal,
applies to storage scope terminals,
such as the Tektronix 4010 series,
as well as to hard copy and
If there is a code to move the cursor to the left edge of the current row,
(Normally this will be carriage-return,
If there is a code to produce an audible signal (bell, beep,
If there is a code (such as backspace)
to move the cursor one position to the left,
that capability should be given as
codes to move to the right, up, and down
.I local cursor motions\^
should not alter the text they pass over;
for example, you would not normally use
unless the terminal has the
because the space would erase the character moved over.
A very important point here is that the local cursor motions encoded
have undefined behavior at the left and top edges of a
Programs should never attempt to backspace around the left edge,
is given, and never attempt to go up off the top
using local cursor motions.
In order to scroll text up,
a program goes to the bottom left corner of the screen and sends the
a program goes to the top left corner of the screen and sends the
when not on their respective corners of the screen.
Parameterized versions of the scrolling sequences are
which have the same semantics as
except that they take one parameter
and scroll that many lines.
They also have undefined behavior
except at the appropriate corner of the screen.
capability tells whether the cursor sticks at the right
edge of the screen when text is output there,
but this does not necessarily apply to
Leftward local motion is defined from the left edge only when
from the left edge will move to the right edge of the previous row.
This is useful for drawing a box around the edge of the screen,
If the terminal has switch-selectable automatic margins,
description usually assumes that this feature is on,
If the terminal has a command
that moves to the first column of the next line,
that command can be given as
It is permissible for this to clear the remainder of the current line,
so if the terminal has no correctly-working \s-2CR\s0 and \s-2LF\s0
it may still be possible to craft a working
out of one or both of them.
These capabilities suffice to describe hardcopy and \*(lqglass-tty\*(rq terminals.
Thus the Teletype model 33 is described as
T3\||\|tty33\||\|33\||\|tty\||\|Teletype model 33:\e
:bl=^G:co#72:cr=^M:do=^J:hc:os:
and the Lear Siegler \s-1ADM\s0\-3 is described as
l3\||\|adm3\||\|3\||\|LSI \s-1ADM\s0-3:\e
:am:bl=^G:cl=^Z:co#80:cr=^M:do=^J:le=^H:li#24:sf=^J:
Cursor addressing and other strings requiring parameters
parameterized string capability, with
while other characters are passed through unchanged.
For example, to address the cursor the
capability is given, using two parameters: the row and column to move to.
(Rows and columns are numbered from zero and refer to the physical screen
visible to the user, not to any unseen memory.
If the terminal has memory-relative cursor addressing,
that can be indicated by an analogous
encodings have the following meanings:
%d output value as in \fIprintf\^\fP %d
%2 output value as in \fIprintf\^\fP %2d
%3 output value as in \fIprintf\^\fP %3d
%. output value as in \fIprintf\^\fP %c
%+\fIx\fP add \fIx\^\fP to value, then do %.
%>\fIxy\fP if value > \fIx\^\fP then add \fIy\^\fP, no output
%r reverse order of two parameters, no output
%i increment by one, no output
%n exclusive-or all parameters with 0140 (Datamedia 2500)
%B BCD (16*(value/10)) + (value%10), no output
%D Reverse coding (value \- 2*(value%16)), no output (Delta Data)
Consider the Hewlett-Packard 2645, which, to get to row 3 and column 12, needs
to be sent \*(lq\eE&a12c03Y\*(rq padded for 6 milliseconds.
of the row and column coordinates is reversed here
and that the row and column
are sent as two-digit integers.
capability is \*(lqcm=6\eE&%r%2c%2Y\*(rq.
The Datamedia 2500 needs the current row and column sent
encoded in binary using \*(lq%.\*(rq.
Terminals that use \*(lq%.\*(rq need to be able to
and to move the cursor up one line on the screen
This is necessary because it is not always safe to transmit
as the system may change or discard them.
must set terminal modes so that tabs are not expanded, so
This turns out to be essential for the Ann Arbor 4080.)
A final example is the Lear Siegler \s-1ADM\s0\-3a,
which offsets row and column
by a blank character, thus \*(lqcm=\eE=%+ %+ \*(rq.
Row or column absolute cursor addressing
can be given as single parameter capabilities
(horizontal position absolute) and
(vertical position absolute).
Sometimes these are shorter than the more general two-parameter sequence
(as with the Hewlett-Packard 2645) and can be used in preference to
If there are parameterized local motions
with a single parameter indicating how many positions to move.
These are primarily useful if the terminal does not have
such as the Tektronix 4025.
If the terminal has a fast way to home the cursor
(to the very upper left corner of the screen), this can be given as
Similarly, a fast way of getting to the lower left-hand corner
this may involve going up with
but a program should never do this itself (unless
make no assumption about the effect of moving up from the home position.
Note that the home position is the same as
cursor address (0,0): to the top left corner of the screen, not of memory.
(Therefore, the \*(lq\eEH\*(rq sequence on Hewlett-Packard terminals
If the terminal can clear from the current position to the end of the
line, leaving the cursor where it is, this should be given as
If the terminal can clear from the current position to the end of the
display, this should be given as
must only be invoked from the first column of a line.
it can be simulated by a request to delete a large number of lines,
If the terminal can open a new blank line
before the line containing the cursor,
this must be invoked only from the first
The cursor must then appear at the left of the newly blank line.
If the terminal can delete the line that the cursor is on, this
this must only be used from the first position on
which take a single parameter
and insert or delete that many lines
If the terminal has a settable scrolling region
the command to set this can be described with the
which takes two parameters: the top and bottom lines of the scrolling region.
The cursor position is, alas, undefined after using this command.
It is possible to get the effect of insert or delete line
using this command \(em the
(save and restore cursor) commands are also useful.
Inserting lines at the top or bottom of the screen can also be done using
on many terminals without a true insert/delete line,
and is often faster even on terminals with those features.
If the terminal has the ability to define a window as part of memory
which all commands affect, it should be given as the parameterized string
The four parameters are the starting and ending lines in memory
and the starting and ending columns in memory, in that order.
capability is described for completeness.
program will support it.)
If the terminal can retain display memory above the screen, then the
capability should be given;
if display memory can be retained
that deleting a line or scrolling may bring non-blank lines up from below
or that scrolling back with
may bring down non-blank lines.
.B Insert/Delete Character
There are two basic kinds of intelligent terminals with respect to
insert/delete character that can be described using
The most common insert/delete character operations affect only the characters
on the current line and shift characters off the end of the line rigidly.
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.
the kind of terminal you have by clearing the screen then typing
text separated by cursor motions.
Type \*(lqabc\ \ \ \ def\*(rq using local
cursor motions (not spaces) between the \*(lqabc\*(rq and the \*(lqdef\*(rq.
Then position the cursor before the \*(lqabc\*(rq and put the terminal in insert
If typing characters causes the rest of the line to shift
rigidly and characters to fall off the end, then your terminal does
not distinguish between blanks and untyped positions.
shifts over to the \*(lqdef\*(rq which then move together around the end of the
current line and onto the next as you insert, then you have the second type of
terminal and should give the capability \fBin\fP, which stands for
While these are two logically separate attributes
and special treatment of untyped spaces),
we have seen no terminals whose insert
mode cannot be described with the single attribute.
can describe both terminals that have an insert mode and terminals
that send a simple sequence to open a blank position on the current line.
the sequence to get into insert mode.
the sequence to leave insert mode.
any sequence that needs to be sent just before
each character to be inserted.
Most terminals with a true insert mode
terminals that use a sequence to open a screen
position should give it here.
(If your terminal has both,
insert mode is usually preferable to
Do not give both unless the terminal actually requires both to be used
If post-insert padding is needed, give this as a number of milliseconds
Any other sequence that may need to be
sent after insertion of a single character can also be given in
If your terminal needs to be placed into an `insert mode'
and needs a special code preceding each inserted character,
can be given, and both will be used.
capability, with one parameter
will repeat the effects of
It is occasionally necessary to move around while in insert mode
to delete characters on the same line
If your terminal allows motion while in
insert mode, you can give the capability
(notably Datamedia's) must not have
to delete a single character,
and delete mode by giving
to enter and exit delete mode
(which is any mode the terminal needs to be placed in for
.B Highlighting, Underlining, and Visible Bells
If your terminal has one or more kinds of display attributes,
these can be represented in a number of different ways.
You should choose one display form as
representing a good high-contrast, easy-on-the-eyes format
for highlighting error messages and other attention getters.
(If you have a choice, reverse video plus half-bright is good,
The sequences to enter and exit standout mode
If the code to change into or out of standout
mode leaves one or even two blank spaces or garbage characters on the screen,
as the TVI 912 and Teleray 1061 do,
should be given to tell how many characters are left.
Codes to begin underlining and end underlining can be given as
Underline mode change garbage is specified by
If the terminal has a code to underline the current character and move
the cursor one position to the right,
such as the Microterm Mime,
Other capabilities to enter various highlighting modes include
(blanking or invisible text),
(enter alternate character set mode), and
(exit alternate character set mode).
Turning on any of these modes singly may or may not turn off other modes.
If there is a sequence to set arbitrary combinations of mode,
(set attributes), taking 9 parameters.
Each parameter is either 0 or 1,
as the corresponding attributes is on or off.
The 9 parameters are, in order: standout, underline, reverse, blink,
dim, bold, blank, protect, and alternate character set.
Not all modes need be supported by
only those for which corresponding attribute commands exist.
program will support this capability, which is defined for compatibility
Terminals with the \*(lqmagic cookie\*(rq glitches
rather than maintaining extra attribute bits for each character cell,
instead deposit special \*(lqcookies\*(rq,
or \*(lqgarbage characters\*(rq,
when they receive mode-setting sequences,
which affect the display algorithm.
such as the Hewlett-Packard 2621,
automatically leave standout
mode when they move to a new line or when the cursor is addressed.
Programs using standout mode
should exit standout mode on such terminals
before moving the cursor or sending a newline.
On terminals where this is not a problem,
capability should be present
to say that this overhead is unnecessary.
a way of flashing the screen to indicate an error quietly
it must not move the cursor.
If the cursor needs to be made more visible than normal
when it is not on the bottom line
(to change, for example, a non-blinking underline into an easier-to-find
block or blinking underline),
If there is a way to make the cursor completely invisible, give that as
which undoes the effects of both of these modes,
If your terminal correctly displays underlined characters
(with no special codes needed)
even though it does not overstrike,
then you should give the capability
If overstrikes are erasable with a blank,
this should be indicated by giving
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 mode
(this applies, for example, to the unshifted Hewlett-Packard 2621 keys).
If the keypad can be set to transmit or not transmit,
Otherwise the keypad is assumed to always transmit.
The codes sent by the left-arrow, right-arrow, up-arrow, down-arrow,
and home keys can be given as
If there are function keys such as f0, f1, ..., f9, the codes they send
If these keys have labels other than the default f0 through f9, the labels
The codes transmitted by certain other special keys can be given:
(clear the tab stop in this column),
(clear to end of screen),
(insert character or enter insert mode),
(scroll backward/up), and
(set a tab stop in this column).
In addition, if the keypad has a 3 by 3 array of keys
including the four arrow keys, then the other five keys can be given as
These keys are useful when the effects of a 3 by 3 directional pad are needed.
capability formerly used to describe \*(lqother\*(rq function keys has been
completely supplanted by the above capabilities.
entry is also used to indicate arrow keys on terminals that have
single-character arrow keys.
It is obsolete but still in use in
which must be run on some minicomputers due to
This field is redundant with
It consists of groups of two characters.
In each group, the first character is what an arrow key sends, and the
second character is the corresponding
For example, the Mime would have \*(lqma=^Hh^Kj^Zk^Xl\*(rq
indicating arrow keys left (^H), down (^K), up (^Z), and right (^X).
(There is no home key on the Mime.)
.B Tabs and Initialization
If the terminal needs to be in a special mode when running
a program that uses these capabilities,
the codes to enter and exit this mode can be given as
This arises, for example, from terminals like the Concept with more than
If the terminal has only memory-relative cursor addressing and not
screen-relative cursor addressing,
a screen-sized window must be fixed into
the display for cursor addressing to work properly.
This is also used for the Tektronix 4025, where
sets the command character to be the one used by
an initialization string for the terminal,
the name of a file containing long initialization strings.
These strings are expected to set the terminal into modes
consistent with the rest of the
They are normally sent to the terminal by the
program each time the user logs in.
They will be printed in the following order:
after the other initializations.)
A pair of sequences that does a harder reset from a totally unknown state
can be analogously given as
These strings are output by the
program, which is used when the terminal gets into a wedged state.
Commands are normally placed in
only if they produce annoying effects on the screen and are not necessary
For example, the command to set the VT100 into 80-column mode
would normally be part of
but it causes an annoying glitch of the screen and is not normally needed
since the terminal is usually already in 80-column mode.
If the terminal has hardware tabs,
the command to advance to the next tab stop can be given as
A \*(lqbacktab\*(rq command which moves leftward to the previous tab stop
if the terminal driver modes indicate that tab stops are being expanded
by the computer rather than being sent to the terminal,
even if they are present,
since the user may not have the tab stops properly set.
If the terminal has hardware tabs that are initially set every
positions when the terminal is powered up, then the numeric parameter
is given, showing the number of positions between tab stops.
This is normally used by the
command to determine whether to set the driver mode for hardware tab
expansion, and whether to set the tab stops.
If the terminal has tab stops that can be saved in nonvolatile memory, the
description can assume that they are properly set.
If there are commands to set and clear tab stops, they can be given as
(clear all tab stops) and
(set a tab stop in the current column of every row).
If a more complex sequence is needed to set the tabs than can be
described by this, the sequence can be placed in
Certain capabilities control padding in the terminal driver.
These are primarily needed by hardcopy terminals and are used by the
program to set terminal driver modes appropriately.
Delays embedded in the capabilities
will cause the appropriate delay bits to be set in the terminal driver.
(padding baud rate) is given, these values can be ignored at baud rates
the delays are given as numeric capabilities
If the terminal requires other than a \s-2NUL\s0 (zero) character as a pad,
Only the first character of the
If the terminal has commands to save and restore the position of the
If the terminal has an extra \*(lqstatus line\*(rq that is not normally used by
software, this fact can be indicated.
If the status line is viewed as an extra line below the bottom line,
Special strings to go to a position in the status line and to return
from the status line can be given as
must leave the cursor position in the same place that it was before
strings can be included in
takes one parameter, which is the column number of the status line
to which the cursor is to be moved.
If escape sequences and other special commands such as tab work while in
the status line, the flag
A string that turns off the status line (or otherwise erases its contents)
The status line is normally assumed to be the same width as the
If the status line is a different width (possibly because the terminal
does not allow an entire line to be loaded), then its width in columns
can be indicated with the numeric parameter
If the terminal can move up or down half a line, this can be
This is primarily useful for superscripts and subscripts on hardcopy
If a hardcopy terminal can eject to the next page (form feed),
If there is a command to repeat a given character a given number of times
(to save time transmitting a large number of identical characters),
this can be indicated with the parameterized string
The first parameter is the character to be repeated and the second is
the number of times to repeat it.
feature that is unlikely to be supported by a program that uses
If the terminal has a settable command character, such as the
Tektronix 4025, this can be indicated with
A prototype command character is chosen which is used in all capabilities.
This character is given in the
capability to identify it.
The following convention is supported on some UNIX systems:
The environment is to be searched for a
all occurrences of the prototype character are replaced by the character
in the environment variable.
is a very bad idea, as it conflicts with
Terminal descriptions that do not represent a specific kind of known
(generic) capability so that programs can complain that they do not know
how to talk to the terminal.
(This capability does not apply to
terminal descriptions for which the escape sequences are known.)
If the terminal uses xoff/xon (\s-2DC3\s0/\s-2DC1\s0)
handshaking for flow control, give
Padding information should still be included so that routines can make
better decisions about costs, but actual pad characters will not be
If the terminal has a \*(lqmeta key\*(rq which acts as a shift key, setting the
8th bit of any character transmitted, then this fact can be indicated with
Otherwise, software will assume that the 8th bit is parity and it will
If strings exist to turn this \*(lqmeta mode\*(rq on and off, they can be given as
If the terminal has more lines of memory than will fit on the screen at once,
the number of lines of memory can be indicated with
An explicit value of 0 indicates that the number of lines is not fixed,
but that there is still more memory than fits on the screen.
If the terminal is one of those supported by the UNIX system virtual
terminal protocol, the terminal number can be given as
Media copy strings which control an auxiliary printer
connected to the terminal can be given as
print the contents of the screen;
turn off the printer; and
When the printer is on, all text sent to the terminal will be sent to the
It is undefined whether the text is also displayed on the terminal screen
takes one parameter and leaves the printer on for as many characters as the
value of the parameter, then turns the printer off.
The parameter should not exceed 255.
is transparently passed to the printer while
Strings to program function keys can be given as
Each of these strings takes two parameters: the function key number
to program (from 0 to 9) and the string to program it with.
Function key numbers out of this range may program undefined keys
in a terminal-dependent manner.
The differences among the capabilities are that
causes pressing the given key to be the same as the user typing the given
causes the string to be executed by the terminal in local mode;
causes the string to be transmitted to the computer.
Unfortunately, due to lack of a definition for string parameters in
supports these capabilities.
.B Glitches and Braindamage
Hazeltine terminals, which do not allow `~' characters to be displayed,
capability, now obsolete, formerly indicated Datamedia terminals,
carriage return then ignore a following linefeed.
Terminals that ignore a linefeed immediately after an
wrap, such as the Concept, should indicate
is required to get rid of standout
(instead of merely writing normal text on top of it),
Teleray terminals, where tabs turn all characters moved over to blanks,
This glitch is also taken to mean that it is not possible
to position the cursor on top of a \*(lqmagic cookie\*(rq, and that
to erase standout mode it is necessary to use delete and insert line.
The Beehive Superbee, which is unable to correctly transmit the
\s-2ESC\s0 or ^C characters, has
indicating that the \*(lqf1\*(rq key is used for \s-2ESC\s0 and \*(lqf2\*(rq for ^C.
(Only certain Superbees have this problem, depending on the ROM.)
Other specific terminal problems may be corrected by adding more
capabilities of the form \fBx\fIx\^\fP.
If there are two very similar terminals,
one can be defined as being just like the other with certain exceptions.
with the name of the similar terminal.
and the combined length of the entries
The capabilities given before
override those in the terminal type invoked by
A capability can be canceled by placing
hn\||\|2621\-nl:ks@:ke@:tc=2621:
defines a \*(lq2621\-nl\*(rq that does not have the
hence does not turn on the function key labels when in visual mode.
This is useful for different modes for a terminal, or for different
Mark Horton added underlining and keypad support
/etc/termcap file containing terminal descriptions
ex(1), more(1), tset(1), ul(1), vi(1), curses(3X), printf(3S),
in UNIX System V Release 2.0.
The transition will be relatively painless if capabilities flagged as
\*(lqobsolete\*(rq are avoided.
Lines and columns are now stored by the kernel as well as in the termcap
Most programs now use the kernel information primarily; the information
in this file is used only if the kernel does not have any information.
allows only 256 characters for string capabilities, and the routines
do not check for overflow of this buffer.
The total length of a single entry (excluding only escaped newlines)
Not all programs support all entries.