termcap(5)termcap(5)Nametermcap - terminal capability data base
Syntax
/etc/termcap
Description
The file is a data base describing terminals used, for example, by and
Terminals are described in by giving a set of capabilities which they
have and by describing how operations are performed. Padding require‐
ments and initialization sequences are included in
Entries in consist of a number of fields separated by colons (:). The
first entry for each terminal gives the names which are known for the
terminal, separated by vertical bars (|). The first name is always 2
characters long and is used by older Version 6 systems, which store the
terminal type in a 16-bit word in a system-wide data base. The second
name given is the most common abbreviation for the terminal, and the
last name given should be a long name fully identifying the terminal.
The second name should contain no blanks. The last name may contain
blanks for readability.
Capabilities
(P) indicates padding is commonly needed for these strings.
(P*) indicates that padding may be based on the number of lines affected.
Name Type Pad? Description
ae str (P) End alternate character set.
al str (P*) Add new blank line.
am bool Terminal has automatic margins.
as str (P) Start alternate character set.
bc str Backspace, if not CTRL/H.
bl str Audible bell character.
bs bool Terminal can backspace with CTRL/H.
bt str (P) Back tab.
bw bool Backspace wraps from column 0 to last column.
CC str Command character in prototype, if terminal-settable.
ca bool Cursor addressable.
cd str (P*) Clear to end of display.
ce str (P) Clear to end of line.
ch str (P) Like cm, but horizontal motion only; line stays the same.
cl str (P*) Clear screen.
cm str (P) Cursor motion.
co num Number of columns in a line.
cr str (P*) Carriage return (default CTRL/M).
cs str (P) Change scrolling region (VT100); like cm.
ct str Clear all tab stops.
cv str (P) Like ch, but vertical only.
da bool Display may be retained above.
dB num Number of millisec of bs delay needed.
db bool Display may be retained below.
dC num Number of millisec of cr delay needed.
dc str (P*) Delete character.
dF num Number of millisec of ff delay needed.
dl str (P*) Delete line.
dm str Delete mode (enter).
dN num Number of millisec of nl delay needed.
do str Move down one line.
ds str Clear host writable status line.
dT num Number of millisec of ta delay needed.
ed str End delete mode.
ei str End insert mode; give ``:ei=:'' if ic.
eo str Can erase overstrikes with a blank.
es bool Standout mode allowed on host writable status line.
ff str (P*) Hard-copy terminal page eject (default CTRL/L).
fs str Close host writable status line to writing.
gt bool Gtty indicates tabs.
hc bool Hard-copy terminal.
hd str Half-line down (forward 1/2 linefeed).
ho str Home cursor (if no cm).
hs bool Host writable status line capabilities.
hu str Half-line up (reverse 1/2 linefeed).
hz str Hazeltine; cannot print tildes (~).
ic str (P) Insert character.
if str Name of file containing is.
im str Insert mode (enter); give ``:im=:'' if ic.
in bool Insert mode distinguishes nulls on display.
ip str (P*) Insert pad after character inserted.
is str Terminal initialization string.
k0-k9 str Sent by “other” function keys 0-9.
kb str Sent by backspace key.
kd str Sent by terminal down arrow key.
ke str Out of “keypad transmit” mode.
kh str Sent by home key.
kl str Sent by terminal left arrow key.
kn num Number of “other” keys.
ko str Termcap entries for other nonfunction keys.
kr str Sent by terminal right arrow key.
ks str Put terminal in “keypad transmit” mode.
ku str Sent by terminal up arrow key.
l0-l9 str Labels on “other” function keys.
le str Move cursor left one place.
li num Number of lines on screen or page.
ll str Last line, first column (if no cm).
ma str Arrow key map, used by vi Version 2 only.
mb str Turn on blinking.
md str Enter bold (extra-bright) mode.
me str Turn off all attributes, normal mode.
mh str Enter dim (half-bright) mode.
mi bool Safe to move while in insert mode.
ml str Memory lock on above cursor.
mr str Enter reverse mode.
ms bool Safe to move while in standout and underline mode.
mu str Memory unlock (turn off memory lock).
nc bool No correctly working carriage return (DM2500,H2000).
nd str Nondestructive space (cursor right).
nl str (P*) Newline character (default \n).
ns bool Terminal is a CRT, but does not scroll.
os bool Terminal overstrikes.
pc str Pad character (rather than null).
pt bool Has hardware tabs (may need to be set with is).
rc str Recover from last save cursor (sc).
rf str Reset file, like initialization file (if) but for reset.
rs str Reset string, like initialization string (is) but for reset.
sc str Save cursor.
se str End stand out mode.
sf str (P) Scroll forwards.
sg num Number of blank chars left by so or se.
so str Begin stand out mode.
sr str (P) Scroll reverse (backwards).
st str Save cursor.
ta str (P) Tab (other than CTRL/I or with padding).
tc str Entry of similar terminal - must be last.
te str String to end programs that use cm.
ti str String to begin programs that use cm.
ts str Open host writable status line to writing.[jA.
uc str Underscore one char and move past it.
ue str End underscore mode.
ug num Number of blank chars left by us or ue.
ul bool Terminal underlines even though it does not overstrike.
up str Upline (cursor up).
us str Start underscore mode.
vb str Visible bell (may not move cursor).
ve str Sequence to end open/visual mode.
vs str Sequence to start open/visual mode.
vt num Virtual terminal number.
xb bool Beehive (f1=escape, f2=CTRL/C).
xn bool A newline is ignored after a wrap (Concept).
xr bool Return acts like ce \r \n (Delta Data).
xs bool Standout not erased by writing over it (HP 264?).
xt bool Tabs are destructive, magic so char (Teleray 1061).
A Sample Entry
The following entry, which describes the Concept-100, is among the more
complex entries in the file as of this writing. This particular `Con‐
cept' entry is outdated and is used as an example only:
c1|c100|concept100:is=\EU\Ef\E7\E5\E8\El\ENH\EK\E\200\Eo&\200:\
:al=3*\E^R:am:bs:cd=16*\E^C:ce=16\E^S:cl=2*^L:cm=\Ea%+ %+:\
:co#80:dc=16\E^A:dl=3*\E^B:ei=\E\200:eo:im=\E^P:in:\
:ip=16*:li#24:mi:nd=\E=:se=\Ed\Ee:so=\ED\EE:ta=8\t:\
:ul:up=\E;:vb=\Ek\EK:xn:
Entries can continue onto multiple lines by giving a backslash (\) as
the last character of a line. Empty fields can be included for read‐
ability (here between the last field on a line and the first field on
the next).
Types of Capabilities
Capabilities in are of three types: Boolean capabilities that indicate
that the terminal has some particular feature; numeric capabilities
giving the size of the terminal or the size of particular delays; and
string capabilities, which give a sequence that can be used to perform
particular terminal operations.
All capabilities have 2-letter codes. For instance, the fact that the
Concept has “automatic margins” (that is, an automatic return and line‐
feed when the end of a line is reached) is indicated by the capability
am. Hence, the description of the Concept includes am. Numeric capa‐
bilities are followed by the number sign (#) and then the value. Thus,
co, which indicates the number of columns the terminal has, gives the
value `80' for the Concept.
Finally, string-valued capabilities, such as ce (clear to end-of-line
sequence), are given by the 2-character code: an equal sign (=) and
then a string ending at the next following colon (:). A delay in mil‐
liseconds may appear after the equal sign (=) in such a capability.
Padding characters are supplied by the editor after the remainder of
the string is sent to provide this delay. The delay can be either an
integer, for example, ``20'', or an integer followed by an asterisk
(*), for example ``3*''. An asterisk (*) indicates that the padding
required is proportional to the number of lines affected by the opera‐
tion, and the amount given is the per-affected-unit padding required.
When an asterisk (*) is specified, it is sometimes useful to give a
delay of the form ``3.5'' to specify a delay per unit to tenths of mil‐
liseconds.
A number of escape sequences are provided in the string-valued capabil‐
ities for easy encoding of characters there. A \E maps to an ESCAPE
character, O^x maps to a CTRL/x for any appropriate x, and the
sequences \n \r \t \b \f give a newline, return, tab, backspace and
formfeed. Finally, characters may be given as three octal digits after
a backslash (\), and the characters circumflex (^) and backslash (\)
may be given as \^ and \\. If it is necessary to place a colon (:) in
a capability, it must be escaped in octal as \072. If it is necessary
to place a null character in a string capability, it must be encoded as
\200. The routines that deal with use C strings and strip the high
bits of the output very late so that a \200 comes out as a \000 would.
Preparing Descriptions
This section outlines how to prepare descriptions of terminals. The
most effective way to prepare a terminal description is by imitating
the description of a similar terminal in and to build up a description
gradually, using partial descriptions with to check that they are cor‐
rect. Be aware that a very unusual terminal may expose deficiencies in
the ability of the file to describe it or bugs in To easily test a new
terminal description, you can set the environment variable TERMCAP to a
pathname of a file containing the description you are working on and
the editor will look there rather than in TERMCAP can also be set to
the termcap entry itself to avoid reading the file when starting up the
editor. This only works on Version 7 systems.
Basic Capabilities
The number of columns on each line for the terminal is given by the co
numeric capability. If the terminal is a CRT, the number of lines on
the screen is given by the li capability. If the terminal wraps around
to the beginning of the next line when it reaches the right margin, it
should have the am capability. If the terminal can clear its screen,
this is given by the cl string capability. If the terminal can
backspace, it should have the bs capability, unless a backspace is
accomplished by a character other than ^H, in which case you should
give this character as the bc string capability. If it overstrikes,
rather than clearing a position when a character is struck over, it
should have the os capability.
A very important point here is that the local cursor motions encoded in
are undefined at the left and top edges of a CRT terminal. The editor
will never attempt to backspace around the left edge, nor will it
attempt to go up locally off the top. The editor assumes that feeding
off the bottom of the screen will cause the screen to scroll up, and
the am capability tells whether the cursor sticks at the right edge of
the screen. If the terminal has switch-selectable automatic margins,
the file usually assumes that this is on, that is, am.
These capabilities suffice to describe hard-copy and “glass-tty” termi‐
nals. Thus, the model 33 teletype is described as:
t3|33|tty33:co#72:os
The Lear Siegler ADM-3 is described as:
cl|adm3|3|lsi adm3:am:bs:cl=^Z:li#24:co#80
Cursor Addressing
Cursor addressing in the terminal is described by a cm string capabil‐
ity, with types of escapes such as %x in it. These substitute to
encodings of the current line or column position, while other charac‐
ters are passed through unchanged. If the cm string is thought of as
being a function, its arguments are the line and then the column to
which motion is desired, and the % encodings have the following mean‐
ings:
%d As in printf, 0 origin
%2 Like %2d
%3 Like %3d
%. Like %c
%+x Adds x to value, then %.
%>xy If value > x adds y, no output.
%r Reverses order of line and column, no output
%i Increments line/column (for 1 origin)
%% Gives a single %
%n Exclusive or row and column with 0140 (DM2500)
%B BCD (16*(x/10)) + (x%10), no output.
%D Reverse coding (x-2*(x%16)), no output. (Delta Data).
Consider the HP2645, which, to get to row 3 and column 12, needs to be
sent \E&a12c03Y padded for 6 milliseconds. Note that the order of the
rows and columns is inverted here, and that the row and column are
printed as 2 digits. Thus, its cm capability is ``cm=6\E&%r%2c%2Y''.
The Microterm 2ACT-IV needs the current row and column sent preceded by
a ^T, with the row and column simply encoded in binary, ``cm=^T%.%.''.
Terminals that use ``%.'' need to be able to backspace the cursor (bs
or bc), and to move the cursor up one line on the screen (up introduced
in the following section). This is necessary because it is not always
safe to transmit \t, \n ^D, and \r, as the system may change or discard
them.
A final example is the LSI ADM-3a, which uses row and column offset by
a blank character; thus “cm=\E=%+ %+ ”.
Cursor Motions
If the terminal can move the cursor one position to the right, leaving
the character at the current position unchanged, this sequence should
be given as nd (non-destructive space). If it can move the cursor up a
line on the screen in the same column, this should be given as up. If
the terminal has no cursor addressing capability, but can home the cur‐
sor (to very upper left corner of screen), this can be given as ho.
Similarly a fast way of getting to the lower left hand corner can be
given as ll. This may involve going up with up from the home position,
but the editor will never do this itself, unless ll does, because it
makes no assumption about the effect of moving up from the home posi‐
tion.
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 dis‐
play, this should be given as cd. The editor only uses cd from the
first column of a line.
Insert/Delete Line
If the terminal can open a new blank line before the line where the
cursor is, this should be given as al; this is done only from the first
position of a line. The cursor must then appear on the newly blank
line. If the terminal can delete the line which the cursor is on, this
should be given as dl. This is done only from the first position on
the line to be deleted. If the terminal can scroll the screen back‐
wards, this can be given as sb, but just al suffices. If the terminal
can retain display memory above, the da capability should be given; if
display memory can be retained below, db should be given. These let
the editor understand that deleting a line on the screen may bring non‐
blank lines up from below or that scrolling back with sb may bring down
nonblank lines.
Insert/Delete Character
There are two basic kinds of intelligent terminals with respect to the
insert/delete character that can be described using The most common
insert/delete character operations affect only the characters on the
current line and shift characters off the end of the line rigidly.
Other terminals, such as the Concept 100 and the Perkin Elmer Owl, make
a distinction between typed and untyped blanks on the screen, shifting
upon an insert or delete only to an untyped blank on the screen which
is either eliminated, or expanded to 2 untyped blanks. You can find
out which kind of terminal you have by clearing the screen and 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” and then moves with it around the end of the current line and
onto the next line as you insert, you have the second type of terminal,
and should give the capability in, which stands for “insert null”. If
your terminal does something different and unusual, you may have to
modify the editor to get it to use the insert mode your terminal
defines. Virtually all terminals that have an insert mode fall into
one of these two classes.
The editor can handle both terminals that have an insert mode and ter‐
minals that send a simple sequence to open a blank position on the cur‐
rent line. Give as im the sequence to get into insert mode, or give it
an empty value if your terminal uses a sequence to insert a blank posi‐
tion. Give as ei the sequence to leave insert mode (give this with an
empty value also, if you gave im so). Give as ic any sequence needed
to be sent just before sending the character to be inserted. Most ter‐
minals with a true insert mode will not give ic. Terminals that send a
sequence to open a screen position should give it here. (Insert mode
is preferable to the sequence to open a position on the screen, if your
terminal has both.) If post insert padding is needed, give this as a
number of milliseconds in ip (a string option). Any other sequence
that may need to be sent after an insert of a single character can also
be given in ip.
It is occasionally necessary to move around while in insert mode to
delete characters on the same line (for example, if there is a tab
after the insertion position). If your terminal allows motion while in
insert mode, you can give the capability mi to speed up inserting in
this case. Omitting mi affects only speed. Some terminals (notably
Datamedia's) must not have mi because of the way their insert mode
works.
Finally, you can specify delete mode by giving dm and ed to enter and
exit delete mode, and dc to delete a single character while in delete
mode.
Highlighting, Underlining, and Visible Bells
If your terminal has sequences to enter and exit standout mode, these
can be given as so and se, respectively. If there are several kinds of
standout mode, such as inverse video, blinking, or underlining. Half-
bright is not usually an acceptable “standout” mode, unless the termi‐
nal is in inverse video mode constantly. The preferred mode is inverse
video by itself. If the code to change into or out of standout mode
leaves 1 or even 2 blank spaces on the screen, as the TVI 912 and Tel‐
eray 1061 do, ug should be given to tell how many spaces are left.
Codes to begin underlining and end underlining can be given as us and
ue, respectively. If the terminal has a code to underline the current
character and move the cursor one space to the right, such as the
Microterm Mime, this can be given as uc. (If the underline code does
not move the cursor to the right, give the code followed by a nonde‐
structive space.)
Many terminals, such as the HP 2621, automatically leave standout mode
when they move to a new line or the cursor is addressed. Programs
using standout mode should exit standout mode before moving the cursor
or sending a newline.
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 terminal should be placed in a different mode dur‐
ing open and visual modes of this can be given as vs and ve, sent at
the start and end of these modes respectively. These can be used to
change, for example, from an underline to a block cursor and back.
If the terminal needs to be in a special mode when running a program
that addresses the cursor, the codes to enter and exit this mode can be
given as ti and te. This arises, for example, from terminals like the
Concept with more than one page of memory. If the terminal has only
memory-relative cursor addressing and not screen-relative cursor
addressing, a one-screen sized window must be fixed into the terminal
for cursor addressing to work properly.
If your terminal correctly generates underlined characters, with no
special codes needed, even though it does not overstrike, you should
give the capability ul. If overstrikes are erasable with a blank, this
should be indicated by 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 (this applies,
for example, to the unshifted HP 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. If there are other keys
that transmit the same code as the terminal expects for the correspond‐
ing function, such as clear screen, the 2-letter codes can be given in
the ko capability, for example, “:ko=cl,ll,sf,sb:”, which says that the
terminal has clear, home down, scroll down, and scroll up keys that
transmit the same thing as the and entries.
The entry is also used to indicate arrow keys on terminals that have
single-character arrow keys. It is obsolete, but still in use in Ver‐
sion 2 of which must be run on some minicomputers due to memory limita‐
tions. This field is redundant with kl, kr, ku, kd, and kh. It con‐
sists of groups of 2 characters. In each group, the first character is
what an arrow key sends; the second character is the corresponding com‐
mand. These commands are for for for for and for For example, the
Microterm Mime would be ``ma=^Kj^Zk^Xl:'' indicating arrow keys left
(^H), down (^K), up (^Z), and right (^X). (There is no home key on the
Mime.)
Miscellaneous
If the terminal requires other than a null (zero) character as a pad,
this can be given as pc.
If tabs on the terminal require padding, or if the terminal uses a
character other than ^I to tab, this can be given as ta.
Hazeltine terminals, which do not allow tildes (~) to be printed,
should indicate hz. Datamedia terminals, which echo carriage-return
linefeed for a carriage return and then ignore a following linefeed,
should indicate nc. Early Concept terminals, which ignore a linefeed
immediately after an am wrap, should indicate xn. If an erase-eol is
required to get rid of standout (instead of merely writing on top of
it), xs should be given. Teleray terminals, where tabs turn all char‐
acters moved over to blanks, should indicate xt. Other specific termi‐
nal problems may be corrected by adding more capabilities of the form
xx.
Other capabilities include is, an initialization string for the termi‐
nal, and if, the name of a file containing long initialization strings.
These strings are expected to properly clear and then set the tabs on
the terminal, if the terminal has settable tabs. If both are given, is
is printed before if. This is useful where if is but is clears the
tabs first.
Similar Terminals
If there are two very similar terminals, one can be defined as being
just like the other with certain exceptions. The string capability tc
can be given with the name of the similar terminal. This capability
must be last and the combined length of the two entries must not exceed
1024. Since routines search the entry from left to right, and since the
tc capability is replaced by the corresponding entry, the capabilities
given at the left override the ones in the similar terminal. A capa‐
bility can be canceled with xx@, where xx is the capability. For exam‐
ple, the following entry defines a 2621nl that does not have the ks or
ke capabilities, and hence does not turn on the function key labels
when in visual mode:
hn|2621nl:ks@:ke@:tc=2621:
This is useful for different modes for a terminal or for different user
preferences.
Restrictions
The and commands allow only 256 characters for string capabilities, and
the routines in do not check for overflow of this buffer. The total
length of a single entry (excluding only escaped newlines) cannot
exceed 1024.
The and entries are specific to the program.
Files
File containing terminal descriptions
See Alsoex(1), more(1), tset(1), ul(1), vi(1), curses(3x), termcap(3x)termcap(5)
