termcap(5) DG/UX 4.30 termcap(5)
NAME
termcap - terminal capability data base
DESCRIPTION
Termcap is a data base of terminal descriptions used by the
termcap(3X) library. All terminals are described in a file
called /etc/termcap. Termcap entries describe, in special
code, how basic operations are performed on a terminal.
They also describe padding requirements, initialization
sequences, and so on. The section entitled "Preparing a
Termcap Description" that appears later explains how to
build a termcap source description.
Entries in Termcap consist of a number of `:'-separated
fields. The first line names the terminal, and the
remaining lines describe its capabilities.
Terminal Names
The first line of for each terminal description gives the
names that are known for the terminal, separated by vertical
bar (|) characters. The first name is always two characters
long for compatibility with older systems which store the
terminal type in a 16-bit word in a system-wide data base.
The second name is the most common abbreviation for the
terminal, the last name should be a long name fully
identifying the terminal, and all others are understood as
synonyms for the terminal name. All names but the first and
last should be in lower case and contain no blanks; the last
name may well contain upper case letters and blanks for
readability.
Terminal names (except for the last, verbose entry) should
be chosen using the following conventions. First, the
vendor and model of the terminal should be specified in the
root name, for example, hp2621. This name should not
contain hyphens. Terminal modes or user preferences should
be indicated by appending a hyphen and an indicator of the
mode. Therefore, a vt100 in 132-column mode would be
vt100-w. The following suffixes should be used where
possible:
Suffix Meaning Example
-w Wide mode (more than 80 columns) vt100-w
-am With automatic margins (usually default) vt100-am
-nam Without automatic margins vt100-nam
-n Number of lines on the screen aaa-60
-na No arrow keys (leave them in local mode) concept100-na
-np Number of pages of memory concept100-4p
-rv Reverse video concept100-rv
Terminal Capabilties
Lines after the first line of a terminal description
Licensed material--property of copyright holder(s) Page 1
termcap(5) DG/UX 4.30 termcap(5)
describe the terminal's capabilities. Capabilities in
termcap are of three general types: Boolean capabilities,
which indicate a terminal's particular features; numeric
capabilities, which give the size of the display or other
attributes; and string capabilities, which give character
sequences that can be used to perform particular terminal
operations.
The table below lists termcap capabilities alphabetically by
name. The second field of the table indicates capability
type. The characters in the Notes field in the table have
the following meanings (more than one may apply to a
capability):
N indicates numeric parameter(s)
P indicates that padding may be specified
* indicates that padding may be based on the number of lines affected
o indicates that the capability is obsolete
"Obsolete" capabilities have no terminfo(4) equivalents;
either they were considered useless, or they have been
subsumed by other capabilities. New software should not
rely on them at all. The last field in the table gives a
short description of the terminal capability.
Name Type Notes Description
ae str (P) End alternate character set mode
AL str (NP*) Add n new blank lines
al str (P*) Add one new blank line
am bool Terminal has automatic margins
as str (P) Start alternate character set mode
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 (motion)
cm str (NP) Screen-relative cursor addressing (motion)
co num Number of columns in a line
cr str (P) Carriage return
cs str (NP) Change scrolling region (VT100)
ct str (P) Clear all tab stops
cv str (NP) Set cursor row (vertical position)
da bool Display may be retained above screen
dB num (o) Milliseconds of bs delay needed (default 0)
db bool Display may be retained below screen
DC str (NP*) Delete n characters
Licensed material--property of copyright holder(s) Page 2
termcap(5) DG/UX 4.30 termcap(5)
dC num (o) Milliseconds of cr delay needed (default 0)
dc str (P*) Delete one character
dF num (o) Milliseconds of ff delay needed (default 0)
DL str (NP*) Delete n lines
dl str (P*) Delete one 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 Move cursor 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 Terminal can erase overstrikes with a blank
EP bool (o) Terminal uses even parity
es bool Escape sequences can be used on status line
ff str (P*) Hardcopy terminal page eject
fs str Return from status line
gn bool Generic line type (e.g. dialup, switch)
hc bool Hardcopy terminal
HD bool (o) Half-duplex
hd str Move a half-line down (forward 1/2 linefeed)
ho str (P) Home cursor
hs bool Terminal has extra "status line"
hu str Move a half-line up (reverse 1/2 linefeed)
hz bool Terminal cannot print tildes (Hazeltine)
IC str (NP*) Insert n blank characters
ic str (P*) Insert one blank character
if str Name of file containing initialization string
im str Enter insert mode
in bool Insert mode distinguishes nulls
ip str (P*) Insert padding after character inserted
is str Terminal initialization string
it num Tabs are initially every n positions
K1 str Sent by keypad upper left key
K2 str Sent by keypad upper right key
K3 str Sent by keypad center key
K4 str Sent by keypad lower left key
K5 str Sent by keypad lower right key
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
Licensed material--property of copyright holder(s) Page 3
termcap(5) DG/UX 4.30 termcap(5)
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 Terminal has a "meta" key (sets eighth 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) Terminal is 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
ll str Move cursor to last line, first column
lm num Lines of memory if > li (0 means varies)
ma str (o) Arrow key map
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 (dim) attribute
mi bool Safe to move while in insert mode
mk str Turn on blank attribute (characters invisible)
ml str (o) Turn on memory lock above cursor
mm str Turn on "meta mode" (transmit eighth bit)
mo str Turn off "meta mode"
mp str Turn on protected attribute
mr str Turn on reverse-video attibute
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 Move cursor right one (non-destructive) space
NL bool (o) \n is newline, not line feed
nl str (o) Newline character if not \n
ns bool (o) Terminal is a CRT but doesn't scroll
nw str (P) Newline (behaves like cr followed by do)
OP bool (o) Terminal uses odd parity
os bool Terminal overstrikes
pb num Lowest baud rate where delays are required
pc str Pad character (default NUL)
pf str Turn off printer
pO str (N) Turn on printer for n bytes
po str Turn on printer
ps str Print contents of screen
Licensed material--property of copyright holder(s) Page 4
termcap(5) DG/UX 4.30 termcap(5)
pt bool (o) Has hardware tabs (may need to be set with is)
rc str (P) Restore cursor to position of last sc
rf str Name of file containing reset string
RI str (NP) Move cursor right n positions
rp str (NP*) Repeat character c n times
rs str Reset terminal completely to sane modes
sa str (NP) Define video attributes
sc str (P) Save cursor position
se str End standout mode
SF str (NP*) Scroll forward (up) n lines
sf str (P) Scroll forward (up) one line
sg num Number of garbage chars left by so or se (default 0)
so str Begin standout mode
SR str (NP*) Scroll backward (down) n lines
sr str (P) Scroll backward (down) one line
st str Set a tab in all rows, current column
ta str (P) Tab to next hardware tab stop
tc str Entry of similar terminal - must be last entry
te str String to end programs that use termcap
ti str String to begin programs that use termcap
ts str (N) Go to status line, column n
UC bool (o) Terminal is 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 Move cursor up one line
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 column 80 (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 Destructive tabs, magic so char (Teleray 1061)
xx bool (o) Tektronix 4025 insert-line
PREPARING A TERMCAP DESCRIPTION
The most effective way to prepare a terminal description is
by imitating the description of a similar terminal in
termcap and building up your description gradually, using
partial descriptions to check that they are correct.
To easily test a new terminal description, set the
environment variable TERMCAP to the absolute pathname of a
Licensed material--property of copyright holder(s) Page 5
termcap(5) DG/UX 4.30 termcap(5)
file containing the description you are working on and
programs 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 a program.
Be aware that a very unusual terminal may expose
deficiencies in the ability of the termcap conventions to
describe it.
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 specified last,
and the combined length of the entries must not exceed 1024
characters. The capabilities given before tc override those
in the terminal type included 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 of a terminal, or for different user preferences.
Parameterized Strings
Cursor addressing and other strings requiring parameters are
described by a parameterized string capability, with
printf(3S)-like escapes %x in it, while other characters are
passed through unchanged. 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), no output
%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
Licensed material--property of copyright holder(s) Page 6
termcap(5) DG/UX 4.30 termcap(5)
cm=6\E&%r%2c%2Y.
The Microterm ACT-IV needs the current row and column sent
simply encoded in binary preceded by a ^T, cm=^T%.%.. Note
that 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, ^H, and \r, as the system may change or
discard them. (Programs using termcap must set terminal
modes so that tabs are not expanded, so \t is safe to send.
This turns out to be essential for the Ann Arbor 4080.)
A final example is the Lear Siegler ADM-3a, which offsets
row and column by a blank character, thus cm=\E=%+ %+ .
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. It is provided here to illustrate the form
and content of a termcap entry, and to provide a point of
reference for the text that follows.
ca|concept100|c100|concept|c104|concept100-4p|HDS Concept-100:\
:al=3*\E^R:am:bl=^G:cd=16*\E^C:ce=16\E^U:cl=2*^L:cm=\Ea%+ %+ :\
:co#80:.cr=9^M:db:dc=16\E^A:dl=3*\E^B:do=^J:ei=\E\200:eo:im=\E^P:in:\
:ip=16*:is=\EU\Ef\E7\E5\E8\El\ENH\EK\E\200\Eo&\200\Eo\47\E:k1=\E5:\
:k2=\E6:k3=\E7:kb=^h:kd=\E<:ke=\Ex:kh=\E?:kl=\E>:kr=\E=:ks=\EX:\
:ku=\E;:le=^H:li#24:mb=\EC:me=\EN\200:mh=\EE:mi:mk=\EH:mp=\EI:\
:mr=\ED:nd=\E=:pb#9600:rp=0.2*\Er%.%+ :se=\Ed\Ee:sf=^J:so=\EE\ED:\
:.ta=8\t:te=\Ev \200\200\200\200\200\200\Ep\r\n:\
:ti=\EU\Ev 8p\Ep\r:ue=\Eg:ul:up=\E;:us=\EG:\
:vb=\Ek\200\200\200\200\200\200\200\200\200\200\200\200\200\200\EK:\
:ve=\Ew:vs=\EW:vt#8:xn:\
:bs:cr=^M:dC#9:dT#8:nl=^J:ta=^I:pt:
Entries may continue onto multiple lines by giving a
backslash (\) as the last character of a line, and empty
fields may be included for readability (here between the
last field on a line and the first field on the next).
Comments may be included on lines beginning with pound sign
(#).
How to Describe Terminal Capabilities in a Termcap Entry
All capabilities have two-letter codes. The fact that the
Concept has automatic margins (that is, an automatic return
and linefeed when the end of a line is reached) is indicated
by the Boolean capability am. Hence the description of the
Concept includes am on the second line.
Numeric capabilities are followed by a pound sign (#) and
then the value. On the third line of the example above, co,
which indicates the number of columns in the display, gives
Licensed material--property of copyright holder(s) Page 7
termcap(5) DG/UX 4.30 termcap(5)
the value "80" for the Concept.
Finally, string-valued capabilities, such as ce (the
sequence to clear-to-end-of-line), are given by the two-
letter code, an equals sign (=), then a string ending at the
next following colon (:). A delay in milliseconds may
appear after the = in such a capability, and causes padding
characters to be supplied by tputs(3X) to provide this delay
after the remainder of the string is sent. The delay can be
either a number, for example, 20, or a number followed by an
asterisk (*), for example, 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 containing a decimal point, for example 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 ,
and \f map to linefeed, return, tab, backspace, and
formfeed, respectively. Finally, characters may be given as
three octal digits after a \, and the characters ^ and \ may
be given as \^ and \\. If it is necessary to place a : in a
capability it must be escaped in 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 eighth bit 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 preceeding example.
TERMCAP TERMINAL CAPABILITIES
The following subsections describe termcap capabilities in
detail.
Basic Capabilities
The number of columns on each line of the display is given
by the co numeric capability. If the display is a CRT, then
the number of lines on the screen is given by the li
capability. If the cursor wraps around to the beginning of
the next line when it reaches the right margin, then it
should have the am capability. If the terminal can clear
its screen, the code to do this is given by the cl string
capability. If the terminal overstrikes (rather than
Licensed material--property of copyright holder(s) Page 8
termcap(5) DG/UX 4.30 termcap(5)
clearing the position when a character is overwritten), it
should have the os capability. If the terminal is a
printing terminal, with no soft copy unit, give it both hc
and os. (os applies to storage scope terminals, such as the
Tektronix 4010 series, as well as to hard copy and APL
terminals.) If there is a code to move the cursor to the
left edge of the current row, give this as cr. (Normally
this will be carriage-return, ^M.) If there is a code to
produce an audible signal (bell, beep, for example), 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 give "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 move the cursor up off the top line using
local cursor motions.
In order to scroll text up, a program moves the cursor to
the bottom left corner of the screen and sends the sf
(index) string. To scroll text down, a program moves the
cursor to the top left corner of the screen and sends the sr
(reverse index) string. The strings sf and sr have
undefined behavior when the cursor is 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 corners 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
Licensed material--property of copyright holder(s) Page 9
termcap(5) DG/UX 4.30 termcap(5)
correctly-working CR and LF it may still be possible to
craft a working nw out of one or both of them.
These capabilities suffice to describe hardcopy and "glass-
tty" terminals. Thus the Teletype model 33 is described as
T3|tty33|33|tty|Teletype model 33:\
:bl=^G:co#72:cr=^M:do=^J:hc:os:
and the Lear Siegler ADM-3 is described as
l3|adm3|3|LSI ADM-3:\
:am:bl=^G:cl=^Z:co#80:cr=^M:do=^J:le=^H:li#24:sf=^J:
Cursor Motions
If the terminal has a fast way to home the cursor (to the
very upper left corner of the screen), this can be given as
ho. Similarly, a fast way of getting to the lower left-hand
corner can be given as ll; this may involve going up with up
from the home position, but a program should never do this
itself (unless ll does), because it can make no assumption
about the effect of moving up from the home position. Note
that the home position is the same as cursor address (0,0):
to the top left corner of the screen, not of memory.
(Therefore, the "\EH" (memory home) sequence on Hewlett-
Packard terminals cannot be used for ho.)
To address the cursor (move it to an absolute position), the
cm capability is given. cm takes two parameters: the row
and column to move the cursor 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 boolean capability.)
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 (for example, 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, as with the
Tektronix 4025.
Area Clears
If the terminal can clear from the current cursor 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 cursor position to the end of the display, this
Licensed material--property of copyright holder(s) Page 10
termcap(5) DG/UX 4.30 termcap(5)
should be given as cd. Programs must output 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; programs
must output this 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; programs must output this
only from the first position on the line to be deleted.
Versions of al and dl which take a single parameter and
insert or delete that many lines can be given as AL and DL.
If the terminal has a settable scrolling region (like the
VT100), the command to set this can be described with the cs
capability, which takes two parameters: the top and bottom
lines of the scrolling region. The cursor position is
undefined after using this command. The program must reset
the cursor position using other termcap capabilities such as
cm or rc. It is possible to get the effect of insert or
delete line using this command - the sc and rc (save and
restore cursor) commands are also useful. Inserting lines
at the top or bottom of the screen can also be done using sr
or sf on many terminals without a true insert/delete line,
and is often faster even on terminals with those features.
If the terminal has the ability to define a window as part
of memory which all commands affect, it should be given as
the parameterized string wi. The four parameters are the
starting and ending lines in memory and the starting and
ending columns in memory, in that order.
If the terminal can retain display memory above the screen,
then the da capability should be given; if display memory
can be retained below, then db should be given. These
indicate that deleting a line or scrolling may bring non-
blank lines up from below, or that scrolling back with sr
may bring down non-blank lines.
Insert/Delete Character
There are two basic kinds of intelligent terminals with
respect to insert/delete character that can be described
using termcap. The most common insert/delete character
operations affect only the characters on the current line
and shift characters off the end of the line rigidly. Other
terminals, such as the Concept-100 and the Perkin Elmer Owl,
make a distinction between typed and untyped blanks on the
screen, shifting upon an insert or delete only to an untyped
blank on the screen which is either eliminated or expanded
to two untyped blanks. You can determine the kind of
Licensed material--property of copyright holder(s) Page 11
termcap(5) DG/UX 4.30 termcap(5)
terminal you have by clearing the screen, and 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, then your terminal does not distinguish between
blanks and untyped positions. If the abc shifts over to the
def which then move together around the end of the current
line and onto the next as you insert, then 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 versus multi-line
insert mode, and special treatment of untyped spaces), we
have seen no terminals whose insert mode cannot be described
with the single attribute.
Termcap can describe both terminals that have an insert mode
and terminals that have a 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 require ic; it is mainly intended
for terminals that use a sequence to open a screen position.
(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 capability). Any other
sequence that may need to be sent after insertion of a
single character can also be given in ip. The IC
capability, with one parameter n, will repeat the effects of
ic n times.
It is occasionally necessary to move the cursor 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 Boolean capability mi to speed up inserting in this
case. Omitting mi will affect only speed. Some terminals
(notably Datamedia) 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 into for dc to
work).
Licensed material--property of copyright holder(s) Page 12
termcap(5) DG/UX 4.30 termcap(5)
Highlighting, Underlining, and Visible Bells
If your terminal has one or more kinds of display
attributes, these can be represented in a number of
different ways. You should choose one display form as
standout mode, representing a good, high-contrast, easy-on-
the-eyes format for highlighting error messages and other
attention getters. (If you have a choice, reverse video
plus half-bright is good, or reverse video alone.) The
sequences to enter and exit standout mode are given as so
and se, respectively. If the code to change into or out of
standout mode leaves one or even two blank spaces or garbage
characters on the screen, as the TVI 912 and Teleray 1061
do, then the numeric capability sg should be given to tell
how many characters are left.
Codes to begin and end underlining can be given as us and
ue, respectively. If changing the underlining mode leaves
blank spaces or garbage characters on the screen, specify
ug, analagous 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 may or may not turn off other modes.
If there is a sequence to set arbitrary combinations of
attributes, this should be given as sa (set attributes),
taking 9 parameters. Each parameter is either 0 or 1, as
the corresponding attribute is on or off. The 9 parameters
are, in order: standout, underline, reverse, blink, dim,
bold, blank, protect, and alternate character set. Not all
modes need be supported by sa, only those for which
corresponding attribute commands exist.
Some terminals, such as the Hewlett-Packard 2621,
automatically leave standout mode when the cursor is moved
to a new line or is addressed. Programs should exit
standout mode on such terminals before moving the cursor or
sending a newline. On terminals where this is not a
problem, the Boolean capability ms should be given to
indicate 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.
Licensed material--property of copyright holder(s) Page 13
termcap(5) DG/UX 4.30 termcap(5)
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 vs
and ve 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 Boolean capability ul.
If overstrikes are erasable with a blank, this should be
indicated by giving the Boolean capability eo.
Keypad
If the terminal has a keypad that transmits codes when the
keys are pressed, termcap can represent. 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 sequences 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 the current 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 the current column). In addition, if the
keypad has a 3 by 3 array of keys including the four arrow
keys, then the other five keys can be given as K1, K2, K3,
K4, and K5. These keys are useful when the effects of a 3
by 3 directional pad are needed. The obsolete ko capability
formerly used to describe "other" function keys has been
completely supplanted by the above capabilities.
The ma entry is also used to indicate arrow keys that send
single-character codes. This field is obsolete and
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 cursor movement from vi(1).
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
Licensed material--property of copyright holder(s) Page 14
termcap(5) DG/UX 4.30 termcap(5)
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 termcap capabilities, the codes to enter
and exit this mode can be given as ti and te. This is
needed, for example, on terminals like the Concept with more
than one page of memory. If the terminal has only memory-
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 should be printed in the
following order: is; setting tabs using ct and st; and
finally if. A pair of sequences that does a harder reset
from a totally unknown state can be analogously given as rs
and if. Commands are normally placed in rs and rf only if
they produce annoying effects on the screen and are usually
unnecessary. 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 in 80-column mode already.
If the terminal has hardware tabs, the command to advance to
the next tab stop can be given as ta (usually ^I). A
"backtab" command which moves leftward to the previous tab
stop can be given as bt. By convention, if the terminal
driver modes indicate that tab stops are being expanded by
the computer rather than being sent to the terminal,
programs should not use ta or bt even if they are present,
since the user may not have the tab stops properly set. If
the terminal has hardware tabs that are initially set every
n positions when the terminal is powered up, then the
numeric parameter it should be given, showing the number of
positions between 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.
Licensed material--property of copyright holder(s) Page 15
termcap(5) DG/UX 4.30 termcap(5)
Delays
Certain capabilities control padding in the terminal driver.
These are primarily needed by hardcopy terminals. The delays
should be embedded as padding information in the cr, sf, le,
ff, and ta capabilities. If the numeric capability pb
(padding baud rate) is given, these values can be ignored at
baud rates below the value of pb. The delays can also be
given as (obsolete) numeric capabilities instead: dC, dN,
dB, dF, and dT.
Miscellaneous
If the terminal requires other than a NUL (zero) character
as padding, 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 Boolean 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) or 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.
Licensed material--property of copyright holder(s) Page 16
termcap(5) DG/UX 4.30 termcap(5)
If the terminal has a settable command character, such as
the Tektronix 4025, this can be indicated with CC. A
prototype command character is chosen which is used in all
capabilities. This character is given in the CC capability
to identify it. The following convention is supported on
some UNIX systems: The environment is 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, however, because 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) Boolean capability
so that programs can complain that they do not know how to
work with that terminal. (This capability does not apply to
virtual terminal descriptions for which the escape sequences
are known.)
If the terminal uses XOFF/XON (DC3/DC1) handshaking for flow
control, give xo. Padding information should still be
included so that routines can make better decisions about
costs, but actual pad characters will not be transmitted.
If the terminal has a "meta key" which acts as a shift key,
setting the eighth bit of any character transmitted, then
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 UNIX system
virtual terminal protocol, the terminal number can be given
as vt.
Media copy strings which control an auxiliary printer
connected to the terminal can be given as ps: print the
contents of the screen; pf: turn off the printer; and po:
turn on the printer. When the printer is on, all text sent
to the terminal will be sent to the printer. It is
undefined whether the text is also displayed on the terminal
screen when the printer is on. A variation pO takes one
parameter and leaves the printer on for as many characters
as the value of the parameter, then turns the printer off.
The parameter should not exceed 255. All text, including
pf, is transparently passed to the printer while pO is in
Licensed material--property of copyright holder(s) Page 17
termcap(5) DG/UX 4.30 termcap(5)
effect.
Glitches and Braindamage
Hazeltine terminals, which do not allow tilde (~) characters
to be displayed, should indicate hz.
The nc capability, now obsolete, formerly indicated
Datamedia terminals, which echo \r \n for carriage return
then ignore a following linefeed.
Terminals that ignore a linefeed immediately after an am
wrap, such as the Concept, should indicate xn.
If ce is required to get rid of standout text (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, should specify xb, indicating that
the "f1" key is used for ESC and "f2" for ^C. (Only certain
Superbees have this problem, depending on the ROM.)
You may correct other specific terminal problems by adding
more capabilities of the form xx.
FILES
/etc/termcap file containing terminal descriptions
SEE ALSO
make(1) and vi(1) in the User's Reference for the DG/UX
System.
termcap(3X), curses(3X), printf(3S), term(5), terminfo(4),
in the Programmer's Reference for the DG/UX System.
captoinfo(1M) and infocmp(1M) in System Manager's Reference
for the DG/UX System.
CAVEATS AND BUGS
Note: termcap is made obsolete by terminfo(4) . 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.
The total length of a single entry (excluding only escaped
Licensed material--property of copyright holder(s) Page 18
termcap(5) DG/UX 4.30 termcap(5)
newlines) may not exceed 1024 characters.
Not all programs support all entries.
Licensed material--property of copyright holder(s) Page 19