The getty program can also recognize a Point to Point Protocol (PPP) negotiation, and, if the pp attribute in gettytab(5) is set, invoke the program given by that string, e.g., pppd(8), instead of login(1). This makes it possible to use a single serial port for either a "shell account with command line interface, or a PPP network link.
The argument
tty
is the special device file in
/dev
to open for the terminal
"ttyh0
(for example,.)
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 or the login prompt will include
the system hostname.
getty uses the ttyaction(3) facility with an action of "getty and user "root to execute site-specific commands when it starts.
Most of the default actions of getty can be circumvented, or modified, by a suitable gettytab(5) table.
The getty program 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.
The
uugetty
program is the same, except that it uses
pidlock(3)
to respect the locks in
/var/spool/lock
of processes that dial out on that tty.
/etc/gettytab
/etc/ttys
/var/spool/lock/LCK..ttyXX
/dev
does not exist.
AT&T UNIX
.