GETTY(8) System Manager's Manual GETTY(8)
getty - set terminal mode
/etc/getty [ type ]
Getty is invoked by init(8) immediately after a terminal is opened,
following the making of a connection. While reading the name getty
attempts to adapt the system to the speed and type of terminal being
Init calls getty with an argument specified by the ttys file entry for
the terminal line. The argument can be used to make getty treat the
line specially. This argument is used as an index into the gettytab(5)
database, to determine the characteristics of the line. If there is no
argument, or there is no such table, the default table is used. If
there is no /etc/gettytab a set of system defaults is used. If indi-
cated by the table located, getty will clear the terminal screen, print
a banner heading, and prompt for a login name. Usually either the ban-
ner 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.
The user's name is terminated by a new-line or carriage-return charac-
ter. The latter results in the system being set to treat carriage
returns appropriately (see tty(4)).
The user's name is scanned to see if it contains any lower-case alpha-
betic characters; if not, and if the name is nonempty, the system is
told to map any future upper-case characters into the corresponding
Finally, login is called with the user's name as argument.
Most of the default actions of getty can be circumvented, or modified,
by a suitable gettytab table.
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
gettytab(5), init(8), login(1), ioctl(2), tty(4), ttys(5).
Currently, the format of /etc/ttys limits the permitted table names to
a single character, this should be expanded.
/etc/ttys should be replaced completely.
4th Berkeley Distribution 18 July 1983 GETTY(8)