GETTY(8)

NAME
getty - set terminal mode

SYNOPSIS
getty [ type [ tty ] ]

DESCRIPTION
Getty is usually invoked by init(8) to open and initialize the tty line, read a login name, and invoke login(1). getty attempts to adapt the system to the speed and type of terminal being used.

The argument tty is the special device file in /dev to open for the terminal (e.g., ``ttyh0''). If there is no argument or the argument is ``-'', the tty line is assumed to be open as file descriptor 0.

The type argument can be used to make getty treat the terminal 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 indicated by the table located, 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 same standard set of speeds.

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 tty(4)).

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.

Finally, login is called with the user's name as an 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 quickly.

DIAGNOSTICS
ttyxx: No such device or address. ttyxx: No such file or address. A terminal which is turned on in the ttys file cannot be opened, likely because the requisite lines are either not configured into the system, the associated device was not attached during boot-time system configuration, or the special file in /dev does not exist.

FILES
/etc/gettytab

SEE ALSO
gettytab(5), init(8), login(1), ioctl(2), tty(4), ttys(5)