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termcap(4)
NAME
termcap - Terminal capability database
SYNOPSIS
/usr/share/lib/termcap
DESCRIPTION
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
The characters in the Notes 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o indicates capability is obsolete
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) 0
nl str (o) Newline character if not 0
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
(terminfo 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
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
There are three types of capabilities listed in the termcap file:
Boolean Capabilities
Indicate particular features that the terminal has
Numeric Capabilities
Specify the size of the display or the size of other attributes.
String Capabilities
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-to-end-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 string-valued 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
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
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
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
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
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, 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, 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
mode-setting 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
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, right-arrow, 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
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
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
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:
ps Print the contents of the screen.
pf Turn off the printer.
po 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:
pk Causes pressing the given key to be the same as the user typing the
given string.
pl Causes the string to be executed by the terminal in local mode.
px 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
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
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.
FILES
/usr/share/lib/termcap
File containing terminal descriptions
RELATED INFORMATION
tset(1), curses(3), printf(3), curs_termcap(3), termcap(3x), terminfo(4)
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Alphabetical listing for T |
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