TERMCAP(F) UNIX System V
Name
termcap - terminal capability data base
Description
The file /etc/termcap is a data base describing terminals.
This data base is used by commands such as vi(C), LyrixO,
Multiplantm and sub-routine packages such as curses(S).
Terminals are described in termcap by giving a set of
capabilities and by describing how operations are performed.
Padding requirements and initialization sequences are
included in termcap.
Entries in termcap consist of a number of fields separated
by colons `:'. The first entry for each terminal gives the
names that are known for the terminal, separated by vertical
bars ( | ). For compatibility with older systems the first
name is always 2 characters long. The second name given is
the most common abbreviation for the terminal and the name
used by vi (C) and ex(C). The last name given should be a
long name fully identifying the terminal. Only the last
name can contain blanks for readability.
Capabilities (including XENIX Extensions)
The following is a list of the capabilities that can be
defined for a given terminal. In this list, (P) indicates
padding can be specified, and (P*) indicates that padding
can be based on the number of lines affected. The
capability type and padding fields are described in detail
in the following section ``Types of Capabilities.''
The codes beginning with uppercase letters (except for CC)
indicate XENIX extensions. They are included in addition to
the standard entries and are used by one or more application
programs. As with the standard entries, not all modes are
supported by all applications or terminals. Some of these
entries refer to specific terminal output capabilities (such
as GS for ``graphics start''). Others describe character
sequences sent by keys that appear on a keyboard (such as PU
for PageUp key). There are also entries that are used to
attribute special meanings to other keys (or combinations of
keys) for use in a particular software program. Some of the
XENIX extension capabilities have a similar function to
standard capabilities. They are used to redefine specific
keys (such as using function keys as arrow keys). The
extension capabilities are included in the /etc/termcap
file, as they are required for some utilities. The more
commonly used extension capabilities are described in more
detail in the section ``XENIX Extensions.''
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 ^H
bs bool Terminal can backspace with ^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
cd str (P*) Clear to end of display
ce str (P) Clear to end of line
CF str Cursor off
ch str (P) Like cm but horizontal motion only,
line stays same
CL str Sent by CHAR LEFT key
cl str (P*) Clear screen
cm str (P) Cursor motion
co num Number of columns in a line
CO str Cursor on
cr str (P*) Carriage return, (default ^M)
cs str (P) Change scrolling region (vt100), like cm
cv str (P) Like ch but vertical only.
CW str Sent by CHANGE WINDOW key
da bool Display may be retained above
DA bool Delete attribute string
db bool Display may be retained below
dB num Number of millisec of bs delay needed
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 Down one line
dT num Number of millisec of tab delay needed
ed str End delete mode
ei str End insert mode; give `:ei=:'
if ic
EN str Sent by END key
eo bool Can erase overstrikes with a blank
ff str (P*) Hardcopy terminal page eject (default ^L)
G1 str Upper-right (1st quadrant) corner character
G2 str Upper-left (2nd quadrant) corner character
Name Type Pad? Description
G3 str Lower-left (3rd quadrant) corner character
G4 str Lower-right (4th quadrant) corner character
GC str Center graphics character (similar to ``+'')
GD str Down-tick character
GE str Graphics mode end
GG num Number of chars taken by GS and GE
GH str Horizontal bar character
GL str Left-tick character
GR str Right-tick character
GS str Graphics mode start
GU str Up-tick character
GV str Vertical bar character
hc bool Hardcopy terminal
hd str Half-line down (forward 1/2 linefeed)
HM str Sent by HOME key (if not kh)
ho str Home cursor (if no cm)
hu str Half-line up (reverse 1/2 linefeed)
hz str Hazeltine; can't print ~'s
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 non-function 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
LD str Sent by line delete key
LF str Sent by line feed key
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
mi bool Safe to move while in insert mode
ml str Memory lock on above cursor
MP str Multiplan initialization string
MR str Multiplan reset string
ms bool Will scroll in stand-out mode
mu str Memory unlock (turn off memory lock)
Name Type Pad? Description
nc bool No correctly working carriage return
(DM2500,H2000)
nd str Non-destructive space (cursor right)
nl str (P*) Newline character (default \n)
ns bool Terminal is a CRT but doesn't scroll
NU str Sent by NEXT UNLOCKED CELL key
os bool Terminal overstrikes
pc str Pad character (rather than null)
PD str Sent by PAGE DOWN key
PN str Start local printing
PS str End local printing
pt bool Has hardware tabs
(may need to be set with is)
PU str Sent by PAGE UP key
RC str Sent by RECALC key
RF str Sent by TOGGLE REFERENCE key
RT str Sent by RETURN key
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)
ta str (P) Tab (other than ^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
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 doesn't overstrike
up str Upline (cursor up)
UP str Sent by up-arrow key (alternate to ku)
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
WL str Sent by WORD LEFT key
WR str Sent by WORD RIGHT key
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 Standard out not erased by writing over it
(HP 264?)
xt bool Tabs are destructive, magic so char
(Teleray 1061)
A Sample Entry
The following entry describes the Concept-100, and is among
the more complex entries in the termcap file. (This
particular Concept 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 may continue over to multiple lines by giving a
backslash (\) as the last character of a line. Empty fields
can be included for readability between the last field on a
line and the first field on the next. Capabilities in
termcap are of three types: Boolean capabilities, which
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.
Types of Capabilities
All capabilities have two letter codes. For instance, the
fact that the Concept has `automatic margins' (i.e., an
automatic return and linefeed when the end of a line is
reached) is indicated by the capability am. The description
of the Concept includes am. Numeric capabilities are
followed by the character `#' 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 two character code,
an `=', and then a string ending at the next following `:'.
A delay in milliseconds may appear after the `=' in such a
capability, and padding characters are supplied by the
editor after the rest of the string is sent to provide this
delay. The delay can be either a integer, e.g., `20', or an
integer followed by an `*', i.e. `3*'. A `*' indicates that
the padding required is proportional to the number of lines
affected by the operation, and the amount given is the per-
affected-unit padding required. When a `*' is specified, it
is sometimes useful to give a delay of the form `3.5' to
specify a delay per unit to tenths of milliseconds.
A number of escape sequences are provided in the string
valued capabilities for easy encoding of characters there. A
\E maps to an ESCAPE character, ^x maps to a control-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 \, and
the characters ^ and \ 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 termcap 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
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 ex 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. To 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 /etc/termcap. TERMCAP can
also be set to the termcap entry itself to avoid reading the
file when starting up the editor.
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 termcap 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 termcap file usually
assumes that this is on (i.e., am).
These capabilities suffice to describe hardcopy and
``glass-tty'' terminals. Thus the model 33 teletype is
described as
t3|33|tty33:co#72:os
while 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 capability. This capability uses printf(S) like
escapes (such as %x) in it. These substitute to encodings
of the current line or column position, while other
characters 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 meanings:
%d replaced by line/column position, 0 origin
%2 like %2d - 2 digit field
%3 like %3d - 3 digit field
%. like printf(S) %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 position (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 two digits. Thus its
cm capability is `cm=6\E&%r%2c%2Y'. The Microterm ACT-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 below). 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, it should be given as up. If
the terminal has no cursor addressing capability, but can
home the cursor (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
position.
Area clears
If the terminal can clear from the current position to the
end of the line, leaving the cursor where it is, the
sequence should be given as ce. If the terminal can clear
from the current position to the end of the display, the
sequence 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, the sequence should be given as al.
Note that 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 on which the cursor
rests, the sequence 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 backwards, the sequence
can be given as sb, but al can suffice. If the terminal can
retain display memory above, the da capability should be
given, and if display memory can be retained below, then db
should be given. These let the editor know that deleting a
line on the screen may bring non-blank lines up from below
or that scrolling back with sb may bring down non-blank
lines.
Insert/delete character
There are two basic kinds of intelligent terminals with
respect to the 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. 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 find out which kind of
terminal you have by clearing the screen and entering text
separated by cursor motions. Enter `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 entering 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'. No known terminals have an
insert mode, not falling into one of these two classes.
The editor can handle both terminals that have an insert
mode and terminals that send a simple sequence to open a
blank position on the current line. Specify im as the
sequence to get into insert mode, or give it an empty value
if your terminal uses a sequence to insert a blank position.
Specify ei as the sequence to leave insert mode (specify
this with an empty value if you also gave im an empty
value). Now specify ic as any sequence needed to be sent
just before sending the character to be inserted. Most
terminals with a true insert mode will not support 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 may also be given in ip.
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. Omitting
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 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 flavors of standout mode (such as reverse
video, blinking, or underlining - half bright is not usually
an acceptable `standout' mode unless the terminal is in
reverse video mode constantly), the preferred mode is
reverse video by itself. It is acceptable, if the code to
change into or out of standout mode leaves one, or even two
blank spaces on the screen, as the TVI 912 and Teleray 1061
do. Although it may confuse some programs slightly, it
cannot be helped.
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, the sequence
can be given as uc. (If the underline code does not move
the cursor to the right, specify the code followed by a
nondestructive space.)
If the terminal has a way of flashing the screen to indicate
an error quietly (a bell replacement), the sequence can be
given as vb; it must not move the cursor. If the terminal
should be placed in a different mode during open and visual
modes of ex, the sequence can be given as vs and ve, sent at
the start and end of these modes respectively. These can be
used to change from a 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 specifying 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
to transmit, enter these codes as ks and ke. Otherwise, the
keypad is assumed always to 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. If there are
function keys such as f0, f1, ..., f9, the codes they send
can be given as k0, k1, ..., k9. If there are other keys
that transmit the same code as the terminal expects for the
corresponding function, such as clear screen, the termcap 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 cl, ll, sf, and sb entries.
The ma entry is also used to indicate arrow keys on
terminals which 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, 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 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, the sequence can be
given as ta.
Terminals that do not allow `~' characters to be displayed
(such as Hazeltines), should indicate hz. Datamedia
terminals that echo carriage-return-linefeed for carriage
return, and then ignore a following linefeed, should
indicate nc. Early Concept terminals, that 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 characters moved over
to blanks, should indicate xt. Other specific terminal
problems may be corrected by adding more capabilities of the
form xx.
If the leading character for commands to the terminal
(normally the escape character) can be set by the software,
specify the command character(s) with the capability CC.
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
properly clear and then set the tabs on the terminal, if the
terminal has settable tabs. If both are given, is is
displayed before if. This is useful where if is
/usr/lib/tabset/std , 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 termlib 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 capability can be canceled with
xx@ where xx is the capability. For example:
hn|2621nl:ks@:ke@:tc=2621:
This defines a 2621nl that does not have the ks or ke
capabilities, and 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 preferences.
XENIX Extensions
Capabilities This table lists the (previously listed) XENIX
extensions to the termcap capabilities. It shows which codes
generate information input from the keyboard to the program
reading the keyboard and which codes generate information
output from the program to the screen.
Name Input/Output Description
CF str Cursor off
CL str Sent by CHAR LEFT key
CO str Cursor on
CW str Sent by CHANGE WINDOW key
DA bool Delete attribute string
EN str Sent by END key
G1 str Upper-right (1st quadrant) corner character
G2 str Upper-left (2nd quadrant) corner character
G3 str Lower-left (3rd quadrant) corner character
G4 str Lower-right (4th quadrant) corner character
G5 str Upper right (1st quadrant) corner character (double)
G6 str Upper left (2nd quadrant) corner character (double)
G7 str Lower left (3rd quadrant) corner character (double)
G8 str Lower right (4th quadrant) corner character (double)
GC str Center graphics character (similar to +)
Gc str Centre graphics character (double)
GD str Down-tick character
Gd str Down tick character (double)
GE str Graphics mode end
GG num Number of chars taken by GS and GE
GH str Horizontal bar character
Gh str Horizontal bar character (double)
GL str Left-tick character
Gl str left-tick character (double)
GR str Right-tick character
Gr str right-tick character (double)
GS str Graphics mode start
GU str Up-tick character
Gu str Up-tick character (double)
GV str Vertical bar character
Gv str Vertical bar character (double)
HM str Sent by HOME key (if not kh)
mb str blinking on
me str blinking off
MP str Multiplan initialization string
MR str Multiplan reset string
NU str Sent by NEXT UNLOCKED CELL key
PD str Sent by PAGE DOWN key
PU str Sent by PAGE UP key
RC str Sent by RECALC key
RF str Sent by TOGGLE REFERENCE key
RT str Sent by RETURN key
UP str Sent by up-arrow key (alternate to ku)
WL str Sent by WORD LEFT key
WR str Sent by WORD RIGHT key
Cursor motion Some application programs make use of special
editing codes. CR and CL move the cursor one character
right and left respectively. WR and WL move the cursor one
word right and left respectively. CW changes windows, when
they are used in the program.
Some application programs turn off the cursor. This is
accomplished using CF for cursor off and CO to turn it back
on.
Graphic mode. If the terminal has graphics capabilities,
this mode can be turned on and off with the GS and GE codes.
Some terminals generate graphics characters from all keys
when in graphics mode (such as the Visual 50). The other G
codes specify particular graphics characters accessed by
escape sequences. These characters are available on some
terminals as alternate graphics character sets (not as a
bit-map graphic mode). The vt100 has access to this kind of
alternate graphics character set, but not to a bit-map
graphic mode.
Files
/etc/termcap File containing terminal descriptions
See Also
ex(C), curses(S), termcap(S), tset(C), vi(C), more(C),
screen(HW)
Credit
This utility was developed at the University of California
at Berkeley and is used with permission.
Notes
ex(C) allows only 256 characters for string capabilities,
and the routines in termcap(S) do not check for overflow of
this buffer. The total length of a single entry (excluding
only escaped newlines) may not exceed 1024.
The ma, vs, and ve entries are specific to the vi(C)
program.
Not all programs support all entries. There are entries
that are not supported by any program.
XENIX termcap extensions are explained in detail in the
software application documentation.
Refer to the screen(HW) manual page, for a description of
the character sequences used by the monitor device on your
specific system.
(printed 2/15/90) TERMCAP(F)