NAME

gettytab — terminal configuration data base

SYNOPSIS

gettytab

DESCRIPTION

The gettytab 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.

Where to run getty(8) processes is normally defined by ttys(5).

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.) The default entry is also normally read by other programs that present login prompts to the user, such as telnetd(8), in order to retrieve the values of the he, hn, im, and if capabilities.

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
ab	bool	false	Auto-baud speed select mechanism for the Micom 600 portselector. Selection is done by looking at how the character `\r' is garbled at 300, 1200, 4800, and 9600 baud.
al	str	NULL	user to auto-login instead of prompting
ap	bool	false	terminal uses any parity
bk	str	0377	alternative end of line character (input break)
b2	str	0377	alternative end of line character (input break)
c0	num	unused	tty control flags to write messages
c1	num	unused	tty control flags to read login name
c2	num	unused	tty control flags to leave terminal as
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 ‘\r\n' after login prompt
cs	bool	false	clear screen based on terminal type in /etc/ttys
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	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
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
i0	num	unused	tty input flags to write messages
i1	num	unused	tty input flags to read login name
i2	num	unused	tty input flags to leave terminal as
if	str	NULL	display named file before prompt, like /etc/issue
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
l0	num	unused	tty local flags to write messages
l1	num	unused	tty local flags to read login name
l2	num	unused	tty local flags to leave terminal as
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
mb	bool	false	do flow control based on carrier
nl	bool	false	terminal has (or might have) a newline character
nn	bool	false	do not prompt for a login name
np	bool	false	terminal uses no parity (i.e. 8-bit characters)
nx	str	default	next table (for auto speed selection)
o0	num	unused	tty output flags to write messages
o1	num	unused	tty output flags to read login name
o2	num	unused	tty output flags to leave terminal as
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)
pp	str	unused	PPP authentication program
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)
st	str	‘^T'	status character
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)
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

The following capabilities are no longer supported by getty(8):

bd	num	0	backspace delay
cb	bool	false	use crt backspace mode
cd	num	0	carriage-return delay
fd	num	0	form-feed (vertical motion) delay
nd	num	0	newline (line-feed) delay
uc	bool	false	terminal is known upper case only

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 c0, c1, c2, i0, i1, i2, l0, l1, l2, o0, o1, or o2 numeric specifications, which can be used to specify (usually in octal, with a leading '0') the exact values of the flags. These flags correspond to the termios c_cflag, c_iflag, c_lflag, and c_oflag fields, respectively. Each these sets must be completely specified to be effective. The f0, f1, and f2 are excepted for backwards compatibility with a previous incarnation of the TTY sub-system. In these flags the bottom 16 bits of the (32 bits) value contain the sgttyb sg_flags field, while the top 16 bits represent the local mode word.

Should getty(8) 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 any of the following character sequences, which expand to information about the environment in which getty(8) is running.

%d

The current date.

%h

The hostname of the machine, which is normally obtained from the system using gethostname(3), but may also be overridden by the hn table entry. In either case it may be edited with the he string. 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. Each character that is neither '@' nor '#' is copied into the final hostname. Surplus '@' and '#' characters are ignored.

%t

The tty name.

%m, %r, %s, %v

The type of machine, release of the operating system, name of the operating system, and version of the kernel, respectively, as returned by uname(3).

%%

A “%” character.

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(1), or having received an alarm signal, and exited. This may be useful to hangup dial in lines.

Output from getty(8) is even parity unless op or np 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(8) does not check parity of input characters in RAW mode.

If pp string is specified and a Point to Point Protocol (PPP) link bringup sequence is recognized, getty(8) will invoke the program referenced by the pp string, e.g. pppd(8). This can be used to handle incoming PPP calls.

SEE ALSO

login(1), gethostname(3), uname(3), termcap(5), ttys(5), getty(8), pppd(8), telnetd(8)

HISTORY

The gettytab file format appeared in 4.2BSD.

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 from 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(5) format is horrid, something more rational should have been chosen.