4.2BSD/usr/man/man8/getty.8

.TH GETTY 8  "18 July 1983"
.UC 4
.SH NAME
getty  \- set terminal mode
.SH SYNOPSIS
.B /etc/getty
[ type ]
.SH DESCRIPTION
.I Getty
is invoked by
.IR  init (8)
immediately after a terminal is opened,
following the making of a connection.
While reading the name
.I getty
attempts to adapt the system to the speed and type of terminal
being used.
.PP
.I Init
calls
.I getty
with an argument specified by the
.I ttys
file entry for the terminal line.
The argument can be used to make
.I getty
treat the line specially.
This argument is used as an index into the
.IR gettytab (5)
database, to determine the characteristics of the line.
If there is no argument, or there is no such table, the
.B default
table is used.
If there is no
.B /etc/gettytab
a set of system defaults is used.
If indicated by the table located,
.I getty
will clear the terminal screen,
print a banner heading,
and prompt for a login name.
Usually either the banner of the login prompt will include
the system hostname.
Then the user's name is read, a character at a time.
If a null character is received, it is assumed to be the result
of the user pushing the `break' (`interrupt') key.
The speed is usually then
changed and the `login:' is typed again;
a second `break' changes the speed again and the `login:'
is typed once more.
Successive `break' characters cycle through the
some standard set of speeds.
.PP
The user's name is terminated by a new-line or
carriage-return character.
The latter results in the system being set to
treat carriage returns appropriately (see
.IR  tty (4)).
.PP
The user's name is scanned to see if
it contains any lower-case alphabetic characters; if not,
and if the name is nonempty, the
system is told to map any future upper-case characters
into the corresponding lower-case characters.
.PP
Finally, login is called with the user's name as argument.
.PP
Most of the default actions of
.I getty
can be circumvented, or modified, by a suitable
.I gettytab
table.
.PP
.I Getty
can be set to timeout after some interval,
which will cause dial up lines to hang up
if the login name is not entered reasonably quickly.
.SH FILES
/etc/gettytab
.SH "SEE ALSO"
gettytab(5), init(8), login(1), ioctl(2), tty(4), ttys(5).
.SH BUGS
Currently, the format of
.B /etc/ttys
limits the permitted table names to a single character,
this should be expanded.
.PP
.B /etc/ttys
should be replaced completely.