NAME
gettytab —
terminal configuration data
base
SYNOPSIS
gettytab |
DESCRIPTION
Thegettytab file is a simplified version of the
termcap(5) data base used to describe terminal lines. The initial
terminal login process
getty(8) accesses the gettytab file each time
it starts, allowing simpler reconfiguration of terminal characteristics. Each
entry in the data base is used to describe one class of terminals.
There is a default terminal class, default, that is used to set global defaults for all other classes. (That is, the default entry is read, then the entry for the class required is used to override particular settings.)
CAPABILITIES
Refer to termcap(5) for a description of the file layout. The default column below lists defaults obtained if there is no entry in the table obtained, nor one in the special default table.
| Name | Type | Default | Description | |
| ap | bool | false | terminal uses any parity | |
| bd | num | 0 | backspace delay | |
| bk | str | 0377 | alternate end of line character (input break) | |
| cb | bool | false | use crt backspace mode | |
| cd | num | 0 | carriage-return delay | |
| ce | bool | false | use crt erase algorithm | |
| ck | bool | false | use crt kill algorithm | |
| cl | str | NULL |
Ta screen clear sequence | |
| co | bool | false | console - add ‘\n’ after login
prompt |
|
| ds | str | ‘^Y’ |
delayed suspend character | |
| dx | bool | false | set DECCTLQ |
|
| ec | bool | false | leave echo OFF | |
| ep | bool | false | terminal uses even parity | |
| er | str | ‘^?’ |
erase character | |
| et | str | ‘^D’ |
end of text
(EOF) character |
|
| ev | str | NULL |
Ta initial environment | |
| f0 | num | unused | tty mode flags to write messages | |
| f1 | num | unused | tty mode flags to read login name | |
| f2 | num | unused | tty mode flags to leave terminal as | |
| fd | num | 0 | form-feed (vertical motion) delay | |
| fl | str | ‘^O’ |
output flush character | |
| hc | bool | false | do NOT hangup line on last close | |
| he | str | NULL |
Ta hostname editing string | |
| hn | str | hostname | hostname | |
| ht | bool | false | terminal has real tabs | |
| ig | bool | false | ignore garbage characters in login name | |
| im | str | NULL |
initial (banner) message | |
| in | str | ‘^C’ |
interrupt character | |
| is | num | unused | input speed | |
| kl | str | ‘^U’ |
kill character | |
| lc | bool | false | terminal has lower case | |
| lm | str | login: | login prompt | |
| ln | str | ‘^V’ |
``literal next'' character | |
| lo | str | /usr/bin/login | program to exec when name obtained | |
| nd | num | 0 | newline (line-feed) delay | |
| nl | bool | false | terminal has (or might have) a newline character | |
| np | bool | false | terminal uses no parity (i.e. 8-bit characters) | |
| nx | str | default | next table (for auto speed selection) | |
| op | bool | false | terminal uses odd parity | |
| os | num | unused | output speed | |
| pc | str | ‘\0’ |
pad character | |
| pe | bool | false | use printer (hard copy) erase algorithm | |
| pf | num | 0 | delay between first prompt and following flush (seconds) | |
| ps | bool | false | line connected to a MICOM port selector | |
| qu | str | ‘^\’ |
quit character | |
| rp | str | ‘^R’ |
line retype character | |
| rw | bool | false | do NOT use raw for input, use cbreak | |
| sp | num | unused | line speed (input and output) | |
| su | str | ‘^Z’ |
suspend character | |
| tc | str | none | table continuation | |
| to | num | 0 | timeout (seconds) | |
| tt | str | NULL |
terminal type (for environment) | |
| ub | bool | false | do unbuffered output (of prompts etc) | |
| uc | bool | false | terminal is known upper case only | |
| we | str | ‘^W’ |
word erase character | |
| xc | bool | false | do | NOT echo control chars as
‘^X’ |
| xf | str | ‘^S’ |
XOFF (stop
output) character |
|
| xn | str | ‘^Q’ |
XON (start
output) character |
If no line speed is specified, speed will not be altered from that which prevails when getty is entered. Specifying an input or output speed will override line speed for stated direction only.
Terminal modes to be used for the output of the message, for input of the login name, and to leave the terminal set as upon completion, are derived from the boolean flags specified. If the derivation should prove inadequate, any (or all) of these three may be overridden with one of the f0, f1, or f2 numeric specifications, which can be used to specify (usually in octal, with a leading '0') the exact values of the flags. Local (new tty) flags are set in the top 16 bits of this (32 bit) value.
Should getty receive a null character (presumed to indicate a line break) it will restart using the table indicated by the nx entry. If there is none, it will re-use its original table.
Delays are specified in milliseconds, the nearest possible delay available in the tty driver will be used. Should greater certainty be desired, delays with values 0, 1, 2, and 3 are interpreted as choosing that particular delay algorithm from the driver.
The cl screen clear string may be preceded by a (decimal) number of milliseconds of delay required (a la termcap). This delay is simulated by repeated use of the pad character pc.
The initial message, and login message, im and lm may include the character sequence %h or %t to obtain the hostname or tty name respectively. (%% obtains a single '%' character.) The hostname is normally obtained from the system, but may be set by the hn table entry. In either case it may be edited with he. The he string is a sequence of characters, each character that is neither '@' nor '#' is copied into the final hostname. A '@' in the he string, causes one character from the real hostname to be copied to the final hostname. A '#' in the he string, causes the next character of the real hostname to be skipped. Surplus '@' and '#' characters are ignored.
When getty execs the login process, given in the lo string (usually “/usr/bin/login”), it will have set the environment to include the terminal type, as indicated by the tt string (if it exists). The ev string, can be used to enter additional data into the environment. It is a list of comma separated strings, each of which will presumably be of the form name=value.
If a non-zero timeout is specified, with to, then getty will exit within the indicated number of seconds, either having received a login name and passed control to login, or having received an alarm signal, and exited. This may be useful to hangup dial in lines.
Output from
getty is even parity unless
op is specified. The op string may be
specified with ap to
allow any parity on input, but generate odd parity output. Note: this only
applies while getty is being run, terminal driver limitations prevent a more
complete implementation.
Getty does not check parity
of input characters in RAW mode.
SEE ALSO
BUGS
The special characters (erase, kill, etc.) are reset to system defaults by login(1). In all cases, '#' or '^H' typed in a login name will be treated as an erase character, and '@' will be treated as a kill character.
The delay stuff is a real crock. Apart form its general lack of flexibility, some of the delay algorithms are not implemented. The terminal driver should support sane delay settings.
The he capability is stupid.
The termcap format is horrid, something more rational should have been chosen.
HISTORY
The gettytab file format appeared in
4.2BSD.