Index of Section 5 Manual Pages
| Interix / SUA | termcap.5 | Interix / SUA |
termcap(5) termcap(5)
termcap
NAME
termcap - terminal capability data base
SYNOPSIS
termcap
DESCRIPTION
The termcap file is a data base 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 colon (:)-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 abbreviation 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
lowercase and contain no blanks; the last name might well contain
uppercase characters and blanks for readability.
Terminal names (except for the last, verbose entry) should be chosen using
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 following
meanings (more than one might apply to a capability):
N Indicates numeric parameter(s)
P Indicates that padding can be specified
* Indicates that padding can be based on the number of lines
affected
o Indicates capability is obsolete
Obsolete capabilities have no terminfo equivalents because 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 later
in this topic).
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 can be retained above the screen.
dB num (o) Milliseconds of bs delay needed (default 0).
db bool Display can be retained below the screen.
DC str (NP*) Delete n characters.
dC num (o) Milliseconds of cr delay needed (default 0).
dc str (P*) Delete character.
dF num (o) Milliseconds of ff delay needed (default 0).
DL str (NP*) Delete n lines.
dl str (P*) Delete line.
dm str Enter delete mode.
dN num (o) Milliseconds of nl delay needed (default 0).
DO str (NP*) Move cursor down: n lines.
do str Down one line.
ds str Disable status line.
dT num (o) Milliseconds of horizontal tab delay needed
(default 0).
dV num (o) Milliseconds of vertical tab delay needed
(default 0).
ec str (NP) Erase n characters.
ed str End delete mode.
ei str End insert mode.
eo bool Can erase overstrikes with a blank.
EP bool (o) Even parity.
es bool Escape can be used on the status line.
ff str (P*) Hardcopy terminal page eject.
fs str Return from status line.
gn bool Generic line type, 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 Path name of program for initialization
(terminfo only).
ip str (P*) Insert pad after character inserted.
is str Terminal initialization string (termcap
only).
it num Tabs initially every n positions.
K1 str Sent by keypad upper left.
K2 str Sent by keypad upper right.
K3 str Sent by keypad center.
K4 str Sent by keypad lower left.
K5 str Sent by keypad lower right.
k0-k9 str Sent by function keys 0-9.
kA str Sent by insert-line key.
ka str Sent by clear-all-tabs key.
kb str Sent by backspace key.
kC str Sent by clear-screen or erase key.
kD str Sent by delete-character key.
kd str Sent by down-arrow key.
kE str Sent by clear-to-end-of-line key.
ke str Out of keypad transmit mode.
kF str Sent by scroll-forward/down key.
kH str Sent by home-down key.
kh str Sent by home key.
kI str Sent by insert-character or enter-insert-mode
key.
kL str Sent by delete-line key.
kl str Sent by left-arrow key.
kM str Sent by insert key while in insert mode.
km bool Has a meta key (shift, sets parity bit).
kN str Sent by next-page key.
kn num (o) Number of function (k0-k9) keys (default 0).
ko str (o) Termcap entries for other non-function keys.
kP str Sent by previous-page key.
kR str Sent by scroll-backward/up key.
kr str Sent by right-arrow key.
kS str Sent by clear-to-end-of-screen key.
ks str Put terminal in keypad transmit mode.
kT str Sent by set-tab key.
kt str Sent by clear-tab key.
ku str Sent by up-arrow key.
l0-l9 str Labels on function keys if not fn.
LC bool (o) Lowercase 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).
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 (eighth bit).
mo str Turn off meta mode.
mp str Turn on protected attribute.
mr str Turn on reverse-video attribute.
ms bool Safe to move in standout modes.
mu str (o) Memory unlock (turn off memory lock).
nc bool (o) No correctly-working cr (Datamedia 2500,
Hazeltine 2000).
nd str Non-destructive space (cursor right).
NL bool (o) \n is newline, not line feed.
nl str (o) Newline character if not \n.
ns bool (o) Terminal is a CRT but does not scroll.
nw str (P) Newline (behaves like cr followed by do).
OP bool (o) Odd parity.
os bool Terminal overstrikes.
pb num Lowest baud where delays are required.
pc str Pad character (default NUL).
pf str Turn off the printer.
pk str Program function key n to type string s
(terminfo only).
pl str Program function key n to execute string s
(terminfo only).
pO str (N) Turn on the printer for n bytes.
po str Turn on the printer.
ps str Print contents of the screen.
pt bool (o) Has hardware tabs (might 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.
t}
ti str String to begin programs that use termcap.
ts str (N) Go to status line, column n.
UC bool (o) Uppercase only.
uc str Underscore one character and move past it.
ue str End underscore mode.
ug num Number of garbage chars left by us or ue
(default 0).
ul bool Underline character overstrikes.
UP str (NP*) Move cursor up n lines.
up str Upline (cursor up).
us str Start underscore mode.
vb str Visible bell (must not move cursor).
ve str Make cursor appear normal (undo vs/vi).
vi str Make cursor invisible.
vs str Make cursor very visible.
vt num Virtual terminal number (not supported on all
systems).
wi str (N) Set current window.
ws num Number of columns in status line.
xb bool Beehive (f1=ESC, f2=^C).
xn bool Newline ignored after 80 cols (Concept).
xo bool Terminal uses xoff/xon (DC3/DC1) handshaking.
xr bool (o) Return acts like ce cr nl (Delta Data).
xs bool Standout not erased by overwriting (Hewlett-
Packard).
xt bool Tabs ruin, magic so char (Teleray 1061).
xx bool (o) Tektronix 4025 insert-line.
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 can continue onto multiple lines by giving a \ as the last
character of a line, and empty fields can be included for readability
(here between the last field on a line and the first field on the next).
Comments can be included on lines beginning with #.
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 (an automatic return
and linefeed when the end of a line is reached) is indicated by the
Boolean capability am. Hence the description of the Concept includes am.
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
sequence) are given by the two-letter code, an '=', then a string ending
at the next following ':'. A delay in milliseconds might appear after the
'=' in such a capability, which causes padding characters to be supplied
by tputs(3) 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 proportional to the number of lines affected by the operation,
and the amount given is the per-affected-line padding required. (In the
case of insert-character, 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
capabilities 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
sequences \n \r \t \b \f map to linefeed, return, tab, backspace, and
formfeed, respectively. Finally, characters can be given as three octal
digits after a \, and the characters ^ and \ can be given as \^ and \\. If
it is necessary to place a : in a capability it must be escaped in octal
as \072. If it is necessary to place a NUL 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.)
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(1) to check that
they are correct. Be aware that a very unusual terminal might expose
deficiencies in the ability of the termcap file to describe it or bugs in
vi(1). 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 path
names (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. 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(1) to edit /etc/passwd at
9600 baud, delete roughly 16 lines from the middle of the screen, then
press 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, the number of lines on the
screen is given by the li capability. If the display wraps around to the
beginning of the next line when the cursor reaches the right margin, it
should have the am capability. If the terminal can clear its screen, the
code to do this is given by the cl string capability. If the terminal
overstrikes (rather than clearing the position when a character is
overwritten), it should have the os capability. If the terminal is a
printing terminal, with no soft copy unit, 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 .SM 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
audible signal (such as a bell or beep), 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,
respectively. 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 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 program
goes to the top-left corner of the screen and sends the sr (reverse index)
string. The strings sf and sr have undefined behavior when not on their
respective corners of the screen. Parameterized versions of the scrolling
sequences are SF and SR, which have the same semantics as sf and sr,
except that they take one parameter and scroll that many lines. They also
have undefined behavior, except at the appropriate corner of the screen.
The am capability tells whether the cursor 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; that is, am. If the terminal has a command that moves to
the first column of the next line, that command can be given as 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
might still be possible to craft a working nw out of one or both of them.
These capabilities suffice to describe hardcopy and glass-tty terminals.
Thus the Teletype model 33 is described as
T3|tty33|33|tty|Teletype model 33:\
@:bl=^G:co#72:cr=^M:do=^J:hc:os:
and the Lear Siegler SM 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
address 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 might 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 .SM 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 move n positions to the
right) these can be given as DO, LE, RI, and UP with a single parameter
indicating how many positions to move. These are primarily useful if the
terminal does not have cm, such as the Tektronix 4025.
Cursor motions
If the terminal has a fast way to home the cursor (to the very upper-left
corner of the screen), this can be given as ho. Similarly, a fast way of
getting to the lower left-hand corner can be given as ll; this can involve
going up with up from the home position, but a program should never do
this itself (unless ll does), because it can make no assumption about the
effect of moving up from the home position. Note that the home position is
the same as cursor address (0,0): to the top left corner of the screen,
not of memory. (Therefore, the \EH sequence on Hewlett-Packard terminals
cannot be used for ho.)
Area clears
If the terminal can clear from the current position to the end of the
line, leaving the cursor where it is, this should be given as ce. If the
terminal can clear from the current position to the end of the display,
this should be given as cd. You can invoke cd only from the first column
of a line. (Therefore, it can be simulated by a request to delete a large
number of lines, if a true cd is not available.)
Insert/delete line
If the terminal can open a new blank line before the line containing the
cursor, this should be given as al; this must be invoked only from the
first position of a line. The cursor must then appear at the left of the
newly blank line. If the terminal can delete the line that the cursor is
on, this should be given as dl; this must only be used from the first
position on the line to be deleted. Versions of al and dl that take a
single parameter and insert or delete that many lines can be given as AL
and DL. If the terminal has a settable scrolling region (like the VT100),
the command to set this can be described with the cs capability, which
takes two parameters: the top and bottom lines of the scrolling region.
Unfortunately, the cursor position is undefined after using this command.
It is possible to get the effect of insert or delete line using this
command -- the sc and rc (save and restore cursor) commands are also
useful. Inserting lines at the top or bottom of the screen can also be
done using sr or sf on many terminals without a true insert/delete line,
and is often faster, even on terminals with those features.
If the terminal is able to define a window as part of memory that 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(5)
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, the da
capability should be given; if display memory can be retained below, db
should be given. These indicate that deleting a line or scrolling can
bring non-blank lines up from below or that scrolling back with sr can
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 that is either
eliminated or expanded to two untyped blanks. You can determine the kind
of terminal you have by clearing the screen then typing text separated by
cursor motions. Type abc def using local cursor motions (not spaces)
between the abc and the def. Then position the cursor before the abc and
put the terminal in insert mode. If typing characters causes the rest of
the line to shift rigidly and characters to fall off the end, your
terminal does not distinguish between blanks and untyped positions. If the
abc shifts over to the def, which then move together around the end of the
current line and onto the next as you insert, you have the second type of
terminal and should give the capability in, which stands for insert null.
While these are two logically separate attributes (one line as compared to
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.
The termcap(5) can describe both terminals that have an insert mode and
terminals that send a simple sequence to open a blank position on the
current line. Give as im the sequence to get into insert mode. Give as ei
the sequence 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 might need to be sent after insertion of a single
character can also be given in ip. If your terminal needs to be placed
into an 'insert mode' and needs a special code preceding each inserted
character, both im/ei and ic can be given, and both will be used. The IC
capability, with one parameter n, will repeat the effects of ic n times.
It is occasionally necessary to move around while in insert mode to delete
characters on the same line 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 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 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 characters on the
screen, as the .SM TVI 912 and Teleray 1061 do, 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
(blinking), md (bold or extra bright), mh (dim or half-bright), mk
(blanking or invisible text), mp (protected), mr (reverse video), me (turn
off all attribute modes), as (enter alternate character set mode), and ae
(exit alternate character set mode). Turning on any of these modes singly
might or might 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
parameters are, in order: standout, underline, reverse, blink, dim, bold,
blank, protect, and alternate character set. Not all modes must be
supported by sa, only those for which corresponding attribute commands
exist. (It is unlikely that a termcap-using program will support this
capability, which is defined for compatibility with terminfo(5).)
Terminals with the magic cookie glitches (sg and ug), rather than
maintaining 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
addressed. Programs using standout mode should exit standout mode on such
terminals before moving the cursor or sending a newline. On terminals
where this is not a problem, the ms capability should be present to say
that this overhead is unnecessary.
If the terminal has a way of flashing the screen to indicate an error
quietly (a bell replacement), this 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 special
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 special
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 character or enter
insert mode), kA (insert line), kN (next page), kP (previous page), kF
(scroll forward/down), kR (scroll backward/up), and kT (set a tab stop in
this column). In addition, if the keypad has a 3 by 3 array of keys
including the four arrow keys, 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 that formerly used
to describe other function keys has been completely supplanted by the
above capabilities.
The ma entry is also used to indicate arrow keys on terminals that have
single-character arrow keys. It is obsolete but still in use in version 2
of vi which must be run on some minicomputers due to memory limitations.
This field is redundant with kl, kr, ku, kd, and kh. It consists of groups
of two characters. In each group, the first character is what an arrow key
sends, and the second character is the corresponding vi command. These
commands are h for kl, j for kd, k for ku, l for kr, and H for kh. For
example, the Mime would have ma=^Hh^Kj^Zk^Xl indicating arrow keys left
(^H), down (^K), up (^Z), and right (^X). (There is no home key on the
Mime.)
Tabs and initialization
If the terminal needs to be in a special mode when running a program that
uses these capabilities, the codes to enter and exit this mode can be
given as ti and te. This arises, for example, from terminals like the
Concept with more than one page of memory. If the terminal has only
memory-relative cursor addressing and not screen-relative cursor
addressing, a screen-sized window must be fixed into the display for
cursor addressing to work properly. This is also used for the Tektronix
4025, where ti sets the command character to be the one used by termcap.
Other capabilities include is, an initialization string for the terminal,
and if, the name of a file containing long initialization strings. These
strings are expected to set the terminal into modes consistent with the
rest of the termcap description. They are normally sent to the terminal by
the tset(1) program each time the user logs in. They will be printed in
the following order: is; setting tabs using ct and st; and finally if. The
terminfo(5) database 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(1) program, which is used
when the terminal gets into a wedged state. The terminfo(5) database 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 might not have the
tab stops properly set. If the terminal has hardware tabs that are
initially set every n positions when the terminal is powered up, the
numeric parameter it is given, showing the number of positions between tab
stops. This is normally used by the tset(1) 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(1) program
to set terminal driver modes appropriately. Delays embedded in the
capabilities cr, sf, le, ff, and ta will cause the appropriate delay bits
to be set in the terminal driver. If pb (padding baud rate) is given,
these values can be ignored at baud rates below the value of pb. For BSD
4.2 tset(1), the delays are given as numeric capabilities dC, dN, dB, dF,
and dT instead.
Miscellaneous
If the terminal requires other than a NUL (zero) character as a pad, this
can be given as pc. Only the first character of the pc string is used.
If the terminal has commands to save and restore the position of the
cursor, 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
position in the same place that it was before ts. If necessary, the sc and
rc strings can be included in ts and fs to get this effect. The capability
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, that is, co. If the status line
is a different width (possibly because the terminal does not allow an
entire line to be loaded), then its width in columns can be indicated with
the numeric parameter ws.
If the terminal can move up or down half a line, this can be indicated
with hu (half-line up) and hd (half-line down). This is primarily useful
for superscripts and subscripts on hardcopy terminals. If a hardcopy
terminal can eject to the next page (form feed), 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
repeat it. (This is a terminfo(5) 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 systems: The environment is to be searched for a CC variable, and if
found, all occurrences of the prototype character are replaced by the
character in the environment variable. This use of the CC environment
variable is a very bad idea, as it conflicts with make(1).
Terminal descriptions that do not represent a specific kind of known
terminal, such as switch, dialup, patch, and network, should include the
gn (generic) capability so that programs can complain that they do not
know how to talk to the terminal. (This capability does not apply to
virtual terminal descriptions for which the escape sequences are known.)
If the terminal uses xoff/xon (DC3/DC1) handshaking for flow control, 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 that acts as a shift key, setting the
eighth bit of any character transmitted, this fact can be indicated with
km. Otherwise, software will assume that the eighth 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 system virtual terminal
protocol, the terminal number can be given as vt.
Media copy strings that 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 might 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(5) supports
these capabilities.
BUGS
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 normal
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 .SM ROM.)
Other specific terminal problems can be corrected by adding more
capabilities of the form xx.
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 canceled 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, and 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
preferences.
FILES
/usr/share/termcap
File containing terminal descriptions. The actual directory depends
upon where INTERIX is installed.
/usr/share/termcap.db
Hash database file containing terminal descriptions. The actual
directory depends upon where INTERIX is installed.
CAVEATS AND BUGS
The Note: termcap functions were replaced by terminfo in AT&T System V
Release 2.0. The transition will be relatively painless if capabilities
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
information in this file is used only if the kernel does not have any
information.
The vi(1) utility allows only 256 characters for string capabilities, and
the routines in termlib do not check for overflow of this buffer. The
total length of a single entry (excluding only escaped newlines) cannot
exceed 1024.
Not all programs support all entries.
SEE ALSO
ex(1)
more(1)
terminfo(5)
tset(1)
vi(1)