getty.8

早期freebsd实现

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.\"     @(#)getty.8	8.1 (Berkeley) 6/4/93
.\"
.Dd June 4, 1993
.Dt GETTY 8
.Os BSD 4
.Sh NAME
.Nm getty
.Nd set terminal mode
.Sh SYNOPSIS
.Nm getty
.Oo 
.Ar type
.Op Ar tty
.Oc
.Sh DESCRIPTION
The
.Nm getty
program
is called by
.Xr init 8
to open and initialize the tty line, read a login name, and invoke
.Xr login 1 .
.Pp
The argument
.Ar tty
is the special device file in
.Pa /dev
to open for the terminal (for example, ``ttyh0'').
If there is no argument or the argument is
.Ql Fl ,
the tty line is assumed to be open as file descriptor 0.
.Pp
The
.Ar type
argument can be used to make
.Nm getty
treat the terminal line specially.
This argument is used as an index into the
.Nm gettytab 5
database, to determine the characteristics of the line.
If there is no argument, or there is no such table, the
.Em default
table is used.
If there is no
.Pa /etc/gettytab
a set of system defaults is used.
If indicated by the table located,
.Nm 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.
.Pp
Most of the default actions of
.Nm getty
can be circumvented, or modified, by a suitable
.Nm gettytab
table.
.Pp
The
.Nm 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.
.Sh DIAGNOSTICS
.Bl -diag
.It "ttyxx: No such device or address."
.It "ttyxx: No such file or address."
A terminal which is turned
on in the
.Xr 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
.Pa /dev
does not exist.
.El
.Sh FILES
.Bl -tag -width /etc/gettytab -compact
.It Pa /etc/gettytab
.El
.Sh SEE ALSO
.Xr gettytab 5 ,
.Xr init 8 ,
.Xr login 1 ,
.Xr ioctl 2 ,
.Xr tty 4 ,
.Xr ttys 5
.Sh HISTORY
A
.Nm getty
program appeared in
.At v6 .