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gettytab 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.
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 ab bool false read a \r first and guess the baud rate from it ap bool false terminal uses 7 bits, 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 screen clear sequence co bool false console - add NEWLINE after login prompt de num 0 delay before first prompt is printed (seconds) ds str ^Y delayed suspend character dx bool false set DECCTLQ ec bool false leave echo OFF ep bool false terminal uses 7 bits, even parity er str ^? erase character et str ^D end of text (EOF) character ev str NULL 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 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 ms str NULL list of terminal modes to set or clear m0 str NULL set modes that apply at the same time as those set by f0 m1 str NULL set modes that apply at the same time as those set by f1 m2 str NULL set modes that apply at the same time as those set by f2 nd num 0 NEWLINE (LINEFEED) delay nl bool false terminal has (or might have) a NEWLINE character nx str default next table (for auto speed selection) op bool false terminal uses 7 bits, odd parity os num unused output speed p8 bool false terminal uses 8 bits, no parity 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 0 line speed (input and output) su str ^Z suspend character tc str none table continuation td num 0 tab delay 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 overrides line speed for stated direction only. If ab is specified, getty will initially read a character from the tty, assumed to be a carriage return, and will attempt to figure out the baud rate based on what the character appears as. It will then look for a table entry for that baud rate; if the line appears to be a 300 baud line, it will look for an entry 300-baud, if it appears to be a 1200 baud line, it will look for an entry 1200-baud, etc..
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.
The ms field can be used to specify modes to be set and cleared. These modes are specified as stty.1v modes; any mode supported by stty may be specified, except for the baud rate which must be specified with the br field. This permits modes not supported by the older terminal interface described in ttcompat.4m to be set or cleared. Thus, to set the terminal port to which the printer is attached to even parity, TAB expansion, no NEWLINE to RETURN/LINEFEED translation, and RTS/CTS flow control enabled, do:
:ms=evenp,-tabs,nl,crtscts:
The m0, m1, and m2 fields can be used to set modes which only apply concurrently with those set by f0, f1, and f2, respectively. The modes specified by ms, m0, m1, and m2 are applied after the modes specified by other existing capabilities.
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 (as with termcap.5 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, copies one character from the real hostname to the final hostname. A `#' in the he string, skips the next character of the real hostname. 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 or p8 is specified. op 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.
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Created by unroff & hp-tools. © somebody (See intro for details). All Rights Reserved. Last modified 11/5/97