termcap - Terminal capability database
/usr/share/lib/termcap
The termcap file is a database describing terminals used
by tset and BSD curses. Terminals are described in the
termcap database by specifying a set of capabilities that
they have and by describing how operations are performed.
Padding requirements and initialization sequences are also
included.
Entries in the termcap database consist of a number of
colon-separated fields. The first entry for each terminal
includes all the names that are used for that terminal,
separated by vertical bars (|). 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
database. The second name is the most common abbreviation
for the terminal. The last name should be a long name,
fully identifying the terminal. Between the second and
last names, include any synonyms commonly used to refer to
that terminal. All names but the first and last should be
in lower case and contain no spaces; the last name can
contain uppercase letters and spaces for readability.
Terminal names (except for the last verbose entry) should
be chosen using certain conventions. The particular piece
of hardware making up the terminal should have a root name
chosen, such as vt100. This name should not contain
hyphens. Any hardware modes or user preferences should be
indicated by appending a hyphen and an indicator of the
mode. Therefore, a vt100 in 132-column mode would be
vt100-w. The following suffixes should be used where possible:
Suffix Meaning Example
-w Wide mode (more than 80 columns) vt100-w
-am With automatic margins (usually default) vt100-am
-nam Without automatic margins vt100-nam
-n Number of lines on the screen aaa-60
-na No arrow keys (leave them in local) concept100-na
-np Number of pages of memory concept100-4p
-rv Reverse video concept100-rv
Capabilities [Toc] [Back]
The characters in the Notes field in the table have the
following meanings (more than one may apply to a capability):
indicates numeric parameter(s) indicates that
padding may be specified indicates that padding may be
based on the number of lines affected indicates capability
is obsolete
Capabilities marked as obsolete have no terminfo equivalents
since they were considered useless, or are subsumed
by other capabilities. New software should not rely on
them at all.
Name Type Notes Description
----------------------------------------------------------------------------
ae str (P) End alternate character set
AL str (NP*) Add n 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 ^H
bl str (P) Audible signal (bell)
bs bool (o) Terminal can backspace with ^H
bt str (P) Back tab
bw bool le (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
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 bs delay needed (default 0)
db bool Display may be retained below the screen
DC str (NP*) Delete n characters
dC num (o) Milliseconds of cr delay needed (default 0)
dc str (P*) Delete character
dF num (o) Milliseconds of ff delay needed (default 0)
DL str (NP*) Delete n lines
dl str (P*) Delete line
dm str Enter delete mode
dN num (o) Milliseconds of nl delay needed (default 0)
DO str (NP*) Move cursor down n lines
do str Down one line
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 n characters
ed str End delete mode
ei str End insert mode
eo bool Can erase overstrikes with a blank
EP bool (o) Even parity
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 (that is, dialup, switch)
hc bool Hardcopy terminal
HD bool (o) Half-duplex
hd str Half-line down (forward 1/2 linefeed)
ho str (P) Home cursor
hs bool Has extra "status line"
hu str Half-line up (reverse 1/2 linefeed)
hz bool Cannot print ~s (Hazeltine)
i1-i3 str Terminal initialization strings (terminfo only)
IC str (NP*) Insert n blank characters
ic str (P*) Insert character
if str Name of file containing initialization string
im str Enter insert mode
in bool Insert mode distinguishes nulls
iP str Pathname of program for initialization (terminfo
only)
ip str (P*) Insert pad after character inserted
is str Terminal initialization string (termcap only)
it num Tabs initially every n 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 "keypad transmit" mode
kF str Sent by scroll-forward/down key
kH str Sent by home-down key
kh str Sent by home 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 "meta" key (shift, sets parity bit)
kN str Sent by next-page key
kn num (o) Number of function (k0-k9) 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 "keypad transmit" 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 "fn"
LC bool (o) Lower-case only
LE str (NP) Move cursor left n positions
le str (P) Move cursor left one position
li num Number of lines on screen or page
ll str Last line, first column
lm num Lines of memory if > li (0 means varies)
ma str (o) Arrow key map (used by vi 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 "meta mode" (8th bit)
mo str Turn off "meta mode"
mp str Turn on protected attribute
mr str Turn on reverse-video attribute
ms bool Safe to move in standout modes
mu str (o) Memory unlock (turn off memory lock)
nc bool (o) No correctly-working cr (Datamedia 2500, Hazeltine
2000)
nd str Non-destructive space (cursor right)
NL bool (o) \n is newline, not line feed
nl str (o) Newline character if not \n
ns bool (o) Terminal is a CRT but does not scroll
nw str (P) Newline (behaves like cr followed by do)
OP bool (o) Odd parity
os bool Terminal overstrikes
pb num Lowest baud where delays are required
pc str Pad character (default NUL)
pf str Turn off the printer
pk str Program function key n to type string s (terminfo
only)
pl str Program function key n to execute string s (terminfo
only)
pO str (N) Turn on the printer for n 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 is)
px str Program function key n to transmit string s (ter-
minfo only)
r1-r3 str Reset terminal completely to sane modes (terminfo
only)
rc str (P) Restore cursor to position of last sc
rf str Name of file containing reset codes
RI str (NP) Move cursor right n positions
rp str (NP*) Repeat character c n times
rs str Reset terminal completely to sane modes (termcap
only)
sa str (NP) Define the video attributes
sc str (P) Save cursor position
se str End standout mode
SF str (NP*) Scroll forward n lines
sf str (P) Scroll text up
sg num Number of garbage chars left by so or se (default 0)
so str Begin standout mode
SR str (NP*) Scroll backward n 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 termcap
ti str String to begin programs that use termcap
ts str (N) Go to status line, column n
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 us or ue (default 0)
ul bool Underline character overstrikes
UP str (NP*) Move cursor up n 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 vs/vi)
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=ESC, f2=^C)
xn bool Newline ignored after 80 cols (Concept)
xo bool Terminal uses xoff/xon (DC3/DC1) handshaking
xr bool (o) Return acts like ce cr nl (Delta Data)
xs bool Standout not erased by overwriting (Hewlett-Packard)
xt bool Tabs ruin, magic so char (Teleray 1061)
xx bool (o) Tektronix 4025 insert-line
Sample Entry [Toc] [Back]
The following sample entry, which describes the Concept-100,
is among the more complex entries that one may
find in a termcap file.
ca|concept100|c100|concept|c104|concept100-4p|HDS Concept-100:\
:al=3*\E^R:am:bl=^G:cd=16*\E^C:ce=16\E^U:cl=2*^L:cm=\Ea%+
%+ :\
:co#80:.cr=9^M:db:dc=16\E^A:dl=3*\E^B:do=^J:ei=\E\200:eo:im=\E^P:in:\
:ip=16*:is=\EU\Ef\E7\E5\E8\El\ENH\EK\E\200\Eo&\200\Eo\47\E:k1=\
E5:\:k2=\E6:k3=\E7:kb=^h:kd=\E<:ke=\Ex:kh=\E?:kl=\E>:kr=\E=:ks=\EX:\
:ku=\E;:le=^H:li#24:mb=\EC:me=\EN\200:mh=\EE:mi:mk=\EH:mp=\EI:\
:mr=\ED:nd=\E=:pb#9600:rp=0.2*\Er%.%+
:se=\Ed\Ee:sf=^J:so=\EE\ED:\ :.ta=8\t:te=\Ev
\200\200\200\200\200\200\Ep\r\n:\ :ti=\EU\Ev
8p\Ep\r:ue=\Eg:ul:up=\E;:us=\EG:\
:vb=\Ek\200\200\200\200\200\200\200\200\200\200\200\200\200\200\
EK:\:ve=\Ew:vs=\EW:vt#8:xn:\
:bs:cr=^M:dC#9:dT#8:nl=^J:ta=^I:pt:
Entries can continue onto multiple lines by giving a \ as
the last character of a line. Empty fields can be
included for readability (here between the last field on a
line and the first field on the next). Comments can be
included on lines beginning with them with the pound sign
(#).
Types of Capabilities [Toc] [Back]
There are three types of capabilities listed in the termcap
file: Indicate particular features that the terminal
has Specify the size of the display or the size of other
attributes. Specify character sequences that can be used
to perform particular terminal operations. All capabilities
have two-letter codes. For instance, the fact that
the Concept has automatic margins (that is, an automatic
return and linefeed when the end of a line is reached) is
indicated by the Boolean capability am in the Concept
description.
Numeric capabilities are followed by the pound sign (#)
character and a number. In the preceding example, co has
the value 80 to indicate 80 columns for the Concept.
Finally, string-valued capabilities, such as ce (clear-toend-of-line
sequence), use a two-letter code followed by
an equal sign (=) and the a descriptive string ending at
the next colon (:). A delay in milliseconds may appear
after the equal sign (=) in such a capability to cause
padding characters to be supplied by tput after the
remainder of the string is sent to provide this delay.
The delay can be either a number or a number followed by
an asterisk (*), for example, 20 or 16*. The asterisk
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, however, the factor is still the
number of lines affected. This value is always 1 unless
the terminal has in and the software uses it.) When an
asterisk is specified, it is sometimes useful to specify a
delay n the form 3.5 to indicate a delay per line to
tenths of milliseconds. (Only one decimal place is
allowed.)
A number of escape sequences are provided in the stringvalued
capabilities for ease in encoding control characters.
The string \E maps to an ESC character, ^x maps to
a Control-x for any appropriate x, and the sequences \n,
\r, \t, \b, and \f map to linefeed, return, tab,
backspace, and formfeed, respectively. You can specify
characters as three octal digits after a backslash (\).
To specify the circumflex (^) or the backslash (\), use \^
or \\ respectively. If you need to include a colon (:) in
a capability, you need to use the octal representation
preceded by a backslash, for example \072. Similarly, to
use the NUL character in a string capability, code it as
\200. (The routines that deal with termcap use C strings
and strip the high order bits of the output very late, so
that a \200 ends up being the same as \000.
Sometimes individual capabilities must be commented out.
To do this, put a period before the capability name. For
example, see the first cr and ta in the preceding example.
Preparing Descriptions [Toc] [Back]
The most effective way to prepare a terminal description
is by imitating the description of a similar terminal
already in the termcap file 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 the ability of the termcap file to describe it or
because of problems with the editor. To easily test a new
terminal description you are working on, you can put it in
your home directory in a file called termcap so programs
will look there before looking in /usr/share/lib/termcap.
You can also set the environment variable TERMPATH 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. (See curs_termcap(3).) The
TERMCAP environment variable is usually set to the termcap
entry itself 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), a severe test is to use
vi to edit the /etc/passwd file at 9600 baud, delete
roughly 16 lines from the middle of the screen, and then
hit the u key several times quickly. If the display
becomes confused, more padding is usually needed. A similar
test can be used for insert-character.
Basic Capabilities [Toc] [Back]
The number of columns on each line of the display is given
by the co numeric capability. If the display is a CRT,
the number of lines on the screen is given by the li capability.
If the display wraps around to the beginning of the next
line when the cursor reaches the right margin, it should
have the am capability. If the terminal can clear its
screen, the code to do this is given by the cl string
capability. If the terminal overstrikes (rather than
clearing the position when a character is overwritten), it
should have the os capability.
If the terminal is a printing terminal, with no soft copy
unit, include both the hc and os capabilities. (The os
capability applies to storage scope terminals, such as the
Tektronix 4010 series, as well as to hard copy and APL
terminals.) If there is a code to move the cursor to the
left edge of the current row, specify this as cr.
(Normally this code is the carriage-return control
sequence, ^M.) If there is a code to produce an audible
signal (bell, beep, and so on) specify this characteristic
as bl.
If there is a code (such as backspace) to move the cursor
one position to the left, specify that capability as le.
Similarly, use the following codes to move to the right,
up, and down: nd, up, and do. These local cursor motions
should not alter the text they pass over; for example, you
would not normally use nd unless the terminal has the os
capability, because the space would erase the character
moved over.
Note that the local cursor motions encoded in the termcap
file have undefined behavior at the left and top edges of
a CRT display. Programs should never attempt to backspace
around the left edge unless the terminal capability bw is
specified 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 sf (index) string.
To scroll text down, a program goes to the top left corner
of the screen and sends the sr (reverse index) string.
The strings sf and sr have undefined behavior when not on
their respective corners of the screen. Parameterized
versions of the scrolling sequences are SF and SR, which
have the same semantics as sf and sr, except that they
take one parameter and scroll that many lines. They also
have undefined behavior except at the appropriate corner
of the screen.
The am capability tells whether the cursor stays at the
right edge of the screen when text is output there, but
does not necessarily apply to nd from the last column.
Leftward local motion is defined from the left edge only
when bw is given; then an le 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, for example.
If the terminal has switch-selectable automatic margins,
the termcap description usually assumes that this feature
is on, that is, am. If the terminal has a command that
moves to the first column of the next line, that command
can be given as nl (newline). It is permissible for this
to clear the remainder of the current line, so if the terminal
has no correctly-working CR and LF, it may still be
possible to craft a working nw out of one or both of them.
These capabilities suffice to describe hardcopy and
"glass-tty" terminals. Thus, the Teletype model 33 is
described as follows:
T3|tty33|33|tty|Teletype model 33:\
:bl=^G:co#72:cr=^M:do=^J:hc:os:
The Lear Siegler ADM is described as follows:
l3|adm3|3|LSI ADM-3:\
:am:bl=^G:cl=^Z:co#80:cr=^M:do=^J:le=^H:li#24:sf=^J:
Parameterized Strings [Toc] [Back]
Cursor addressing and other strings requiring parameters
are described by a parameterized string capability, with
escapes similar to those used with printf %x in it, while
other characters are passed through unchanged. For example,
to address the cursor, the cm capability is specified
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 CM capability.)
The % encodings have the following meanings:
%% output `%'
%d output value as in printf %d
%2 output value as in printf %2d
%3 output value as in printf %3d
%. output value as in printf %c
%+x add x to value, then do %.
%>xy if value > x then add y, 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 "\E&a12c03Y" padded for 6
milliseconds. Note that the order of the row and column
coordinates is reversed here and that the row and column
are sent as two-digit integers. Thus its cm capability is
"cm=6\E&%r%2c%2Y".
The Microterm ACT-IV needs the current row and column sent
simply encoded in binary preceded by a ^T "cm=^T%.%.".
Terminals that use "%." need to be able to backspace the
cursor (le) and to move the cursor up one line on the
screen (up). This is necessary because it is not always
safe to transmit \n, ^D and \r, as the system may change
or discard them. (Programs using termcap must set terminal
modes so that tabs are not expanded, so \t is safe to
send. This turns out to be essential for the Ann Arbor
4080.)
A final example is the Lear Siegler ADM-3a, which offsets
row and column by a blank character, thus "cm=\E=%+ %+".
Row or column absolute cursor addressing can be given as
single parameter capabilities ch (horizontal position
absolute) and cv (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 cm. If there are parameterized
local motions (that is, move n positions to the right)
these can be given as DO, LE, RI, and UP with a single
parameter indicating how many positions to move. These
are primarily useful if the terminal does not have cm,
such as the Tektronix 4025.
Cursor Motions [Toc] [Back]
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 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 a program
should never do this itself (unless ll does), because it
can 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 "\EH" sequence
on Hewlett-Packard terminals cannot be used for ho.)
Area Clears [Toc] [Back]
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 ce. If the terminal can clear from the
current position to the end of the display, this should be
given as cd. The cd capability must only be invoked from
the first column of a line. (Therefore, it can be simulated
by a request to delete a large number of lines, if a
true cd is not available.
Insert/Delete Line
If the terminal can open a new blank line before the line
containing the cursor, this should be given as al; this
must be invoked only from the first position of a line.
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 should be given as dl; this must only be used
from the first position on the line to be deleted. Versions
of al and dl which take a single parameter and
insert or delete that many lines can be given as AL and
DL. If the terminal has a settable scrolling region (like
the VT100), the command to set this can be described with
the cs capability, 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 -- the sc and rc (save and restore cursor)
commands are also useful. Inserting lines at the top
or bottom of the screen can also be done using sr or sf 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 wi. The four parameters are the
starting and ending lines in memory and the starting and
ending columns in memory, in that order. (This termcap
capability is described for completeness. It is unlikely
that any program using termcap will support it.)
If the terminal can retain display memory above the
screen, then the da capability should be given; if display
memory can be retained below, db should be specified.
These indicate that deleting a line or scrolling may bring
non-blank lines up from below or that scrolling back with
sr may bring down non-blank lines.
Insert/Delete Character
There are two basic kinds of intelligent terminals with
respect to insert/delete character that can be described
using termcap. 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.
You can determine the kind of terminal you have by clearing
the screen then typing text separated by cursor
motions. Type "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 typing 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". Although these are two logically separate
attributes (one line as opposed to multi-line insert
mode, and special treatment of untyped spaces), almost all
terminals can be described with the single attribute.
The termcap file 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. Specify as im
the sequence to get into insert mode. Specify as ei the
sequence to leave insert mode. Then, specify as ic any
sequence that needs to be sent just before each character
to be inserted. Most terminals with a true insert mode
will not use ic; terminals that use a sequence to open a
screen position should specify it here. (If your terminal
has both, insert mode is usually preferable to ic. Do not
specify both unless the terminal actually requires both to
be used in combination.)
If post-insert padding is needed, specify this as a number
of milliseconds in ip (a string option). Any other
sequence that may need to be sent after insertion of a
single character can also be given in ip. If your terminal
needs to be placed into an "insert mode" and needs a
special code preceding each inserted character, both im/ei
and ic can be given, and both will be used. The IC capability,
with one parameter n, will repeat the effects of
ic n times.
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) cannot have mi because of the way
their insert mode works.
Finally, you can specify dc to delete a single character,
DC with one parameter n to delete n characters, and delete
mode by giving dm and ed to enter and exit delete mode
(which is any mode the terminal needs to be placed in for
dc to work.)
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
"standout mode" representing a good high-contrast, easyon-the-eyes
format for highlighting error messages and
other attention getters. (If you have a choice, reverse
video plus half-bright is good, or reverse video alone.)
The sequences to enter and exit standout mode are given as
so and se respectively. If the code to change into or out
of standout mode leaves one or even two blank spaces or
stray characters on the screen, as the TVI 912 and Teleray
1061 do, specify sg to tell how many characters are left.
Codes to begin underlining and end underlining can be
given as us and ue, respectively. Underline mode change
garbage is specified by ug, similar to sg. 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, this can be specified as uc.
Other capabilities to enter various highlighting modes
include mb (blinking), md (bold or extra bright), mh (dim
or half-bright), mk (blanking or invisible text), mp (protected),
mr (reverse video), me (turn off all attribute
modes), as (enter alternate character set mode), and ae
(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, this should be specified as sa (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 sa; only those for
which corresponding attribute commands exist. (It is
unlikely that a program using termcap will support this
capability, which is defined for compatibility with terminfo.)
Terminals with the "magic cookie" anomalies (sg and ug)
rather than maintaining extra attribute bits for each
character cell, instead deposit special "cookies", or
other kinds of stray characters, when they receive modesetting
sequences, which affect the display algorithm.
Some terminals, 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, the ms capability should be
present to say that this overhead is unnecessary.
If the terminal has a way of flashing the screen to indicate
an error quietly (a bell replacement), this capability
can be specified using vb; 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), specify this sequence as vs. If
there is a way to make the cursor completely invisible,
specify that as vi. The capability ve, which undoes the
effects of both of these modes, should also be specified.
If your terminal correctly displays 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 [Toc] [Back]
If the terminal has a keypad that transmits codes when the
keys are pressed, this information can be specified. 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, give these
codes as ks and ke. Otherwise the keypad is assumed to
always transmit. The codes sent by the left-arrow, rightarrow,
up-arrow, down-arrow, and home keys can be given as
kl, kr, ku, kd, and kh, respectively.
If there are function keys such as f0, f1, ..., f9, the
codes they send can be given as k0, k1, "" ..., k9. If
these keys have labels other than the default f0 through
f9, the labels can be given as 10, 11, "" ..., 19.
The codes transmitted by certain other special keys can be
specified: kH (home down), kb (backspace), ka (clear all
tabs), kt (clear the tab stop in this column), kC (clear
screen or erase), kD (delete character), kL (delete line),
kM (exit insert mode), kE (clear to end of line), kS
(clear to end of screen), kI (insert character or enter
insert mode), kA (insert line), kN (next page), kP (previous
page), kF (scroll forward/down), kR (scroll backward/up),
and kT (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 K1, K2, K3, K4, and K5. These keys are useful
when the effects of a 3 by 3 directional pad are needed.
The obsolete ko capability formerly used to describe
"other" function keys has been completely supplanted by
the above capabilities.
The ma entry is also used to indicate arrow keys on terminals
that 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, and 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 have "ma=^Hh^Kj^Zk^Xl" indicating
arrow keys left (^H), down (^K), up (^Z), and right
(^X). (There is no home key on the Mime.)
Tabs and Initialization [Toc] [Back]
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 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 screen-sized window must be fixed
into the display for cursor addressing to work properly.
This is also used for the Tektronix 4025, where ti sets
the command character to be the one used by termcap.
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 set the terminal into modes consistent with the rest of
the termcap description. They are normally sent to the
terminal by the tset program each time the user logs in.
They will be printed in the following order: is; setting
tabs using ct and st; and finally if. (The terminfo file
uses i1-i2 instead of is and runs the program iP and
prints i3 after the other initializations.) A pair of
sequences that does a harder reset from a totally unknown
state can be analogously given as rs and if. These
strings are output by the reset program, which is used
when the terminal gets into a wedged state. (The terminfo
program uses r1-r3 instead of rs.)
Commands are normally placed in rs and rf only if they
produce annoying effects on the screen and are not necessary
when logging in. For example, the command to set the
VT100 into 80-column mode would normally be part of is,
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 ta (usually ^I). A
backtab command which moves leftward to the previous tab
stop can be given as bt. By convention, if the terminal
driver modes indicate that tab stops are being expanded by
the computer rather than being sent to the terminal, programs
should not use ta or bt 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 n positions when the terminal is powered up, the
numeric parameter it is given, showing the number of positions
between tab stops. This is normally used by the
tset 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 termcap description can assume
that they are properly set.
If there are commands to set and clear tab stops, they can
be given as ct (clear all tab stops) and st (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 is or if.
Delays [Toc] [Back]
Certain capabilities control padding in the terminal
driver. These are primarily needed by hardcopy terminals
and are used by the tset program to set terminal driver
modes appropriately. Delays embedded in the capabilities
cr, sf, le, ff, and ta will cause the appropriate delay
bits to be set in the terminal driver. If pb (padding
baud rate) is given, these values can be ignored at baud
rates below the value of pb. For systems based on 4.2BSD
tset, the delays are given as numeric capabilities dC, dN,
dB, dF, and dT instead.
Miscellaneous [Toc] [Back]
If the terminal requires other than a NUL (zero) character
as a pad, this can be given as pc. Only the first character
of the pc string is used.
If the terminal has commands to save and restore the position
of the cursor, specify them as sc and rc.
If the terminal has an extra status line 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, then the capability hs should be specified.
Special strings to go to a position in the status line and
to return from the status line can be given as ts and fs.
(The fs capability must leave the cursor position in the
same place that it was before ts. If necessary, the sc and
rc strings can be included in ts and fs to get this
effect.) The ts capability 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 es can be specified. A string that turns off the
status line (or otherwise erases its contents) should be
specified as ds. The status line is normally assumed to
be the same width as the rest of the screen, that is, co.
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 ws.
If the terminal can move up or down half a line, this can
be indicated with hu (half-line up) and hd (half-line
down). This is primarily useful for superscripts and subscripts
on hardcopy terminals. If a hardcopy terminal can
eject to the next page (form feed), specify this as ff
(usually ^L).
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 rp. The first parameter is the character
to be repeated and the second is the number of times
to repeat it. (This is a terminfo feature that is
unlikely to be supported by a program that uses termcap.)
If the terminal has a settable command character, such as
the Tektronix 4025, this can be indicated with CC. A prototype
command character is chosen which is used in all
capabilities. This character is given in the CC capability
to identify it. The following convention is supported
on some UNIX systems: The environment is to be searched
for a CC variable, and if found, all occurrences of the
prototype character are replaced by the character in the
environment variable. This use of the CC environment
variable is a very bad idea, as it conflicts with make(1).
Terminal descriptions that do not represent a specific
kind of known terminal, such as switch, dialup, patch, and
network, should include the gn (generic) capability so
that programs can complain that they do not know how to
talk to the terminal. (This capability does not apply to
virtual terminal descriptions for which the escape
sequences are known.)
If the terminal uses xoff/xon (DC3/DC1) handshaking for
flow control, specify xo. Padding information should
still be included so that routines can make better decisions
about costs, but actual pad characters will not be
transmitted.
If the terminal has a meta key which acts as a shift key
setting the eighth bit of any character transmitted, this
fact can be indicated with km. Otherwise, software will
assume that the 8th bit is parity and it will usually be
cleared. If strings exist to turn this meta mode on and
off, they can be given as mm and mo.
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 lm. 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
specified as vt.
Media copy strings which control an auxiliary printer connected
to the terminal can be given as follows: Print the
contents of the screen. Turn off the printer. Turn on
the printer.
When the printer is on, all text sent to the terminal will
be sent to the printer. It is undefined whether the text
is also displayed on the terminal screen when the printer
is on. A variation, pO, 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. All text, including pf, is transparently
passed to the printer while pO is in effect.
Strings to program function keys can be specified as pk,
pl, and px. 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
as follows: Causes pressing the given key to be the same
as the user typing the given string. 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 termcap, only terminfo supports these capabilities.
Cautions [Toc] [Back]
Hazeltine terminals, which do not allow tilde ( ) characters
to be displayed, should indicate hz.
The nc capability, now obsolete, formerly indicated Datamedia
terminals, which echo \r \n for carriage return then
ignore a following linefeed.
Terminals that ignore a linefeed immediately after an am
wrap, such as the Concept, should indicate xn.
If ce is required to get rid of standout (instead of
merely writing normal text on top of it), xs should be
specified.
Teleray terminals, where tabs turn all characters moved
over to blanks, should indicate xt (destructive tabs).
This glitch is also taken to mean that it is not possible
to position the cursor on top of a "magic cookie", 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 ESC or ^C characters, has xb, indicating that the
f1 key is used for ESC and the f2 key 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 xx.
Note
In UNIX System V Release 2.0, termcap was replaced by terminfo.
If you are making a transition, avoid using any
capabilities marked as obsolete.
Lines and columns are now stored by the kernel as well as
in the termcap entry. Most programs now use the kernel
information primarily; the information in this file is
used only if the kernel does not have any information.
The total length of a single entry (excluding only escaped
newlines) cannot exceed 1024 bytes, including a null terminator.
Not all programs support all entries.
Similar Terminals [Toc] [Back]
If there are two very similar terminals, one can be
defined as being like the other with certain exceptions.
The string capability tc can be specified with the name of
the similar terminal. This capability must be last, and
the combined length of the entries must not exceed 1024
bytes, including a null terminator. The capabilities
given before tc override those in the terminal type
invoked by tc. A capability can be canceled by placing
xx@ to the left of the tc invocation, where xx is the
capability. For example, the following entry defines a
"2621-nl" that does not have the ke or ke capabilities,
hence does not turn on the function key labels when in
visual mode.
hn|2621-nl:ks@:ke@:tc=2621:
This is useful for different modes for a terminal, or for
different user preferences.
File containing terminal descriptions
tset(1), curses(3), printf(3), curs_termcap(3), termcap(3x), terminfo(4) delim off
termcap(4)
[ Back ] |
