The Terminal Database File

The terminal database file, which is similar to the termcap file supplied with many UNIX systems, may be edited to add new terminals to the ones it currently supports. Existing entries in the file may also be edited, if needed, to describe your terminal.

Each line of this file is either blank, a comment (marked by a "#" in column 1), or a definition of a terminal. You can continue a "line" on following lines by ending the line to be continued with a "\" (see below for an example). The "\" character must be the last character on the line.

A terminal definition consists of several fields, separated by colons. The end of the line marks the end of the definition. The first field is always the name of the terminal. Several names can be placed here, separated by a vertical bar ("|"). The rest of the fields consist of codes that describe various terminal functions. Most of these codes are followed by an equals sign and a coded string that describes how to operate that particular function.

Here is a generic representation of a terminal database file entry, where TNnis a terminal name, tf is a terminal function code, and cs is a coded string to accomplish the function (some terminal function codes are self-defining and do not need a coded string):


The coded string that describes a function is just a representation of the control-sequence (or sequences) that the terminal uses to activate that function. These strings consist of the literal characters used in the control-sequence. Several special forms are recognized to aid in describing the control-sequence. The following abbreviations are supported:

\E an escape character
\n a newline (control-J)
\r a carriage return (control-M)
\t a tab (control-I)
\b a backspace (control-H)
\f a form-feed (control-L)
^X X is any character, treated as control-X
\nnn    three digits treated as an octal value

The following is a list of all of the supported function codes.

AC Attributes used by clear screen
AT Special color for IBM 3164 terminal
B1 - B8 Background color 1-8
BL Blink
C1 - C8    Foreground color 1-8
DI De-initialization string
DL Default intensity is low
DP Disable print mode
EP Enable print mode
GA Graphics on and off are characters
GE Graphic escape
GF Graphics off
GM Graphics map
GO Graphics on
GX Graphics movement glitch
HI High-intensity, normal video
LO Low-intensity, normal video
NM Normal Video (only if ìsgî set)
NS Screen does not scroll when corner is used
OC One color can be displayed at a time
RA Reverse video, alternate intensity
RB Reverse video, blink
RU Reverse video, underline
RV Reverse video
UL Underline
W3 Set terminal width to 132 columns
W8 Set terminal width to 80 columns
al Insert (add) line
bc Backspace cursor (defaults to ^H)
cd Clear to end-of-screen
ce Clear to end-of-line
cl Clear screen
cm Cursor positioning
co Number of screen columns (default 80)
dl Delete line
do Down one line (defaults to ^J)
is Initialization string
is1 Additional initialization string
is2 Additional initialization string
li Number of screen lines (default 24)
nd Non-destructive space
sg Standout-mode glitch (uses magic cookies)
tc Continue description with another entry
up Cursor up one line
ve Set cursor to normal
vi Set cursor to invisible
vs Set cursor to bright

The following codes are also available to represent various keys. Most terminals have only a subset of this full set.

K1 - K0    Function keys 11 - 20
K? Help
KA Attention
KB Bottom
KC Clear
KD Do (command)
KE End
KF Find
KI Insert character
KL Page left
KM Mark (select)
KP Print
KR Page right
KS Send
KT Top
KV Save
KX Delete character
Kc Cancel
Kl Word left
Kr Word right
Kx Exit
k1 - k0 Function keys 1 - 10
kA Insert line
kB Tab left
kE Clear to end
kL Delete line
kN Page Down
kP Page Up
kd Down arrow
kh Home
kl Left arrow
kr Right arrow
ku Up arrow
U1 - U0 User defined key 1 - 10
A1 - A0 User defined key 11 - 20

All of the function codes described with lower-case characters are identical to ones found in the UNIX termcap file. These sequences can be taken verbatim from termcap and included in the ACUCOBOL-GT terminal database file when you are adding a new terminal entry.

To help with this discussion, an example of an entry for a DEC VT-100 will be developed. At each step of the example, the new portion of the entry will be in bold type. Initially, we need to assign a set of names that we want to use to refer to the terminal. For example:

vt100|vt-100|DEC VT-100:

This allows for any of the names vt100, vt-100 or DEC VT-100 to be used for the TERM or A_TERM variable. By convention, the last name in the list is a long, descriptive name.