GETTYTAB(5)

NAME
gettytab - terminal configuration data base

SYNOPSIS
gettytab

DESCRIPTION
The gettytab file is a simplified version of the capfile(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 capfile(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 | \377 | alternative end of line character (input break)
(VEOL)
b2 | str | \377 | alternative end of line character (input break)
(VEOL2)
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
(VDSUSP)
dx | bool | false | set DECCTLQ
ec | bool | false | leave echo
OFF
ep | bool | false | terminal uses even parity
er | str | ‘^?’ | erase character
(VERASE)
et | str | ‘^D’ | end of text
(VEOF) 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
(VDISCARD)
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
(VINTR)
is | num | unused | input speed
kl | str | ‘^U’ | kill character
(VKILL)
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
(VLNEXT)
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
(VQUIT)
rp | str | ‘^R’ | line retype character
(VREPRINT)
rw | bool | false | do
NOT use RAW for input, use CBREAK
sp | num | unused | line speed (input and output)
st | str | ‘^T’ | status character
(VSTATUS)
su | str | ‘^Z’ | suspend character
(VSUSP)
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
(VWERASE)
xc | bool | false | do
NOT echo control chars as ‘^X’
xf | str | ‘^S’ | XOFF
(stop output) character (VSTOP)
xn | str | ‘^Q’ | XON
(start output) character (VSTART)

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 im, and login message 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), capfile(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.