TERMCAP(5) BSD Reference Manual TERMCAP(5)NAMEtermcap - terminal capability database
SYNOPSIStermcapDESCRIPTION
The termcap file is a database describing terminals, used, for example,
by vi(1) and curses(3). Terminals are described in termcap by giving a
set of capabilities that they have and by describing how operations are
performed. Padding requirements and initialization sequences are included
in termcap.
Entries in termcap 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 given is the most common ab-
breviation 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 last should be in lower case and
contain no blanks; the last name may well contain upper case characters
and blanks for readability.
Terminal names (except for the last, verbose entry) should be chosen us-
ing the following conventions. The particular piece of hardware making up
the terminal should have a root name chosen, thus "hp2621" This name
should not contain hyphens. Modes that the hardware can be in 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 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 function field in the table have the follow-
ing 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o Indicates capability is obsolete.
"Obsolete" capabilities 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 (see BUGS sec-
tion 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 bs delay needed (default 0).
db bool Display may be retained below the screen.
DC str (NP*) Delete n characters.
dC num (o) Milliseconds cr delay needed (default 0).
dc str (P*) Delete character.
dF num (o) Milliseconds 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 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, for example 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 ``~'' (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 center.
K3 str Sent by keypad upper right.
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 (see BUGS
section below).
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 doesn't 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 columns (Concept).
xo bool Terminal uses xoff/xon (DC3/DC1) handshak-
ing.
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.
A Sample Entry
The following entry, which describes the Concept-100, is among the more
complex entries in the termcap file as of this writing.
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 may continue onto multiple lines by giving a '\' 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 '#'.
Types of Capabilities
Capabilities in termcap are of three types: Boolean capabilities, which
indicate particular features that the terminal has; numeric capabilities,
giving the size of the display or the size of other attributes; and
string capabilities, which give 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 (an
automatic return and linefeed when the end of a line is reached) is indi-
cated by the Boolean capability am. Hence the description of the Concept
includes am.
Boolean capabilities are defined by their name, fo. They have no argu-
ment. The presence of a boolean capability name sets its value to true. A
capability value will be reverted to false, by appending a @ char after
the name, such as fo@.
Numeric capabilities are followed by the character `#' then the value. In
the example above co, which indicates the number of columns the display
has, gives the value `80' for the Concept.
Finally, string-valued capabilities, such as ce (clear-to-end-of-line se-
quence) 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
tputs after the remainder of the string is sent to provide this delay.
The delay can be either a number, such as `20', or a number followed by
an `*', such as `3*'. An `*' indicates that the padding required is pro-
portional 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 lines affected; this
is always 1 unless the terminal has in 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 capabili-
ties for easy encoding of control characters there. \E maps to an ESC
character, ^X maps to a control-X for any appropriate X, and the se-
quences \n \r \t \b \f map to linefeed, return, tab, backspace, and
formfeed, respectively. Finally, characters may be given as three octal
digits after a \, and the characters ^ and \ may be given as \^ and \\.
If it is necessary to place a : in a capability it must be escaped in oc-
tal as \072. If it is necessary to place a NUL character in a string ca-
pability it must be encoded as \200. (The routines that deal with termcap
use C strings and strip the high bits of the output very late, so that a
\200 comes out as a \000 would.)
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 example above.
Preparing Descriptions
The most effective way to prepare a terminal description is by imitating
the description of a similar terminal in termcap and to build up a
description gradually, using partial descriptions with vi to check that
they are correct. Be aware that a very unusual terminal may expose defi-
ciencies in the ability of the termcap file to describe it or bugs in vi.
To easily test a new terminal description you are working on you can put
it in your home directory in a file called .termcap and programs will
look there before looking in /usr/share/misc/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 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 /etc/passwd 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.
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, then 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,
then 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, give it both hc and os. (os
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, give this as cr. (Normally
this will be carriage-return, ^M.) If there is a code to produce an audi-
ble signal (bell, beep, etc.), give this as bl.
If there is a code (such as backspace) to move the cursor one position to
the left, that capability should be given as le. Similarly, codes to move
to the right, up, and down should be given as nd, up, and do, respective-
ly. 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.
A very important point here is that the local cursor motions encoded in
termcap have undefined behavior at the left and top edges of a CRT
display. Programs should never attempt to backspace around the left edge,
unless bw 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 sf (index) string. To scroll text down, a pro-
gram 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 sticks at the right edge of
the screen when text is output there, but this 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, i.e. am. If the terminal has a command that
moves to the first column of the next line, that command can be given as
nw (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" termi-
nals. Thus the Teletype model 33 is described as
T3|tty33|33|tty|Teletype model 33:\
:bl=^G:co#72:cr=^M:do=^J:hc:os:
and the Lear Siegler ADM-3 is described as
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 printf(3)-like escapes %x in it,
while other characters are passed through unchanged. For example, to ad-
dress the cursor the cm 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 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 Datamedia 2500 needs the current row and column sent encoded in
binary using "%.". 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 (e.g., 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 pri-
marily 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 in-
volve 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 posi-
tion 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. cd 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 po-
sition on the line to be deleted. Versions of al and dl which take a sin-
gle 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 pos-
sible 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 terminfo
capability is described for completeness. It is unlikely that any
termcap- using program 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, then
db should be given. 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 ei-
ther 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 charac-
ters 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. 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 in-
sert, then you have the second type of terminal and should give the capa-
bility in, which stands for "insert null". While these are two logically
separate attributes (one line vs. multi-line insert mode, and special
treatment of untyped spaces), we have seen no terminals whose insert mode
cannot be described with the single attribute.
termcap can describe both terminals that have an insert mode and termi-
nals that send a simple sequence to open a blank position on the current
line. Give as im the sequence to get into insert mode. Give as ei the se-
quence to leave insert mode. Now give 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 give ic; 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 ic. Do not give both unless the terminal
actually requires both to be used in combination.) If post-insert padding
is needed, give this as a number of milliseconds in ip (a string option).
Any other sequence that may need to be sent after 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, then 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 (e.g., 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. Omit-
ting mi will affect only speed. Some terminals (notably Datamedia's) must
not have mi because of the way their insert mode works.
Finally, you can specify 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 garbage charac-
ters on the screen, as the TVI 912 and Teleray 1061 do, then sg should be
given 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 given as uc.
Other capabilities to enter various highlighting modes include mb (blink-
ing), md (bold or extra bright), mh (dim or half-bright), mk (blanking or
invisible text), mp (protected), mr (reverse video), me (turn off all at-
tribute modes), as (enter alternate character set mode), and ae (exit al-
ternate 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 given as sa (set attributes), taking 9 parameters. Each parameter is
either 0 or 1, as the corresponding attributes is on or off. The 9 param-
eters are, in order: standout, underline, reverse, blink, dim, bold,
blank, protect, and alternate character set. Not all modes need be sup-
ported by sa, only those for which corresponding attribute commands ex-
ist. (It is unlikely that a termcap-using program will support this capa-
bility, which is defined for compatibility with terminfo.)
Terminals with the "magic cookie" glitches (sg and ug), rather than main-
taining extra attribute bits for each character cell, instead deposit
special "cookies", or "garbage 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 ad-
dressed. 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 can be given as 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), give this sequence as vs. If
there is a way to make the cursor completely invisible, give that as vi.
The capability ve, which undoes the effects of both of these modes,
should also be given.
If your terminal correctly displays underlined characters (with no spe-
cial codes needed) even though it does not overstrike, then you should
give the capability ul. If overstrikes are erasable with a blank, this
should be indicated by giving eo.
Keypad
If the terminal has a keypad that transmits codes when the keys are
pressed, this information can be given. Note that it is not possible to
handle terminals where the keypad only works in local 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 l0, l1, l9. The codes transmitted by certain other spe-
cial keys can be given: 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 char-
acter or enter insert mode), kA (insert line), kN (next page), kP (previ-
ous 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 form-
erly used to describe "other" function keys has been completely supplant-
ed 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 com-
mand. 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 ar-
row 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 address-
ing, a screen-sized window must be fixed into the display for cursor ad-
dressing 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.
(Terminfo 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. (Terminfo 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 ini-
tially set every n positions when the terminal is powered up, then 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 capa-
bilities 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 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 cur-
sor, give 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 given.
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. (fs must leave the cursor po-
sition 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 capabil-
ity ts 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
given. A string that turns off the status line (or otherwise erases its
contents) should be given as ds. The status line is normally assumed to
be the same width as the rest of the screen, i.e. co. If the status line
is a different width (possibly because the terminal does not allow an en-
tire 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 ter-
minal can eject to the next page (form feed), give 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 re-
peat 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 ter-
minal, 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,
give 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
8th bit of any character transmitted, then 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 ter-
minal protocol, the terminal number can be given as vt.
Media copy strings which control an auxiliary printer connected to the
terminal can be given as ps: print the contents of the screen; pf: turn
off the printer; and 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 given 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 that 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; and 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.
Glitches and Braindamage
Hazeltine terminals, which do not allow `~' 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 nor-
mal text on top of it), xs should be given.
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 "f2"
for ^C. (Only certain Superbees have this problem, depending on the ROM.)
Other specific terminal problems may be corrected by adding more capabil-
ities of the form x x.
Similar Terminals
If there are two very similar terminals, one can be defined as being just
like the other with certain exceptions. The string capability tc can be
given with the name of the similar terminal. This capability must be
last, and the combined length of the entries must not exceed 1024. The
capabilities given before tc override those in the terminal type invoked
by tc. A capability can be cancelled by placing xx@ to the left of the tc
invocation, where xx is the capability. For example, the entry
hn|2621-nl:ks@:ke@:tc=2621:
defines a "2621-nl" that does not have the ks or ke capabilities, 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 user prefer-
ences.
FILES
/usr/share/misc/termcap File containing terminal descriptions.
/usr/share/misc/termcap.db Hash database file containing terminal
descriptions (see cap_mkdb(1)).
SEE ALSOcap_mkdb(1), ex(1), more(1), tset(1), ul(1), vi(1), curses(3), printf(3),
termcap(3), term(7)HISTORY
The termcap file format appeared in 3BSD.
CAVEATS AND BUGS
The Note: termcap functions were replaced by terminfo in AT&T System V
UNIX Release 2.0. The transition will be relatively painless if capabili-
ties flagged as "obsolete" are avoided.
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 infor-
mation in this file is used only if the kernel does not have any informa-
tion.
Vi allows only 256 characters for string capabilities, and the routines
in termcap(3) do not check for overflow of this buffer. The total length
of a single entry (excluding only escaped newlines) may not exceed 1024.
Not all programs support all entries.
MirOS BSD #10-current March 6, 1993 13
