NAME
gettytab —
terminal configuration data
base
SYNOPSIS
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 |
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 Ta
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 ’ Ta
delayed suspend character |
dx |
bool |
false |
set DECCTLQ |
ec |
bool |
false |
leave echo OFF |
ep |
bool |
false |
terminal uses even parity |
er |
str |
‘^? ’ Ta
erase character |
et |
str |
‘^D ’ Ta
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 |
fl |
str |
‘^O ’ Ta
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 |
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 Ta
initial (banner) message |
in |
str |
‘^C ’ Ta
interrupt character |
is |
num |
unused |
input speed |
kl |
str |
‘^U ’ Ta
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 ’ Ta
``literal next'' character |
lo |
str |
/usr/bin/login Ta
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 ’ Ta
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 |
‘^\ ’ Ta
quit character |
rp |
str |
‘^R ’ Ta
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 ’ Ta
status character |
su |
str |
‘^Z ’ Ta
suspend character |
tc |
str |
none |
table continuation |
to |
num |
0 |
timeout (seconds) |
tt |
str |
NULL Ta
terminal type (for environment) |
ub |
bool |
false |
do unbuffered output (of prompts etc) |
we |
str |
‘^W ’ Ta
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),
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.