.Dd December 16, 2024
.Dt GETTY 8
.Os
.Sh NAME
.Nm getty
.Nd initialize a terminal session
.Sh SYNOPSIS
.Nm
.Op Fl 5678beflnoR
.Op Fl h Ar height
.Op Fl s Ar speed
.Op Fl t Ar term
.Op Fl w Ar width
.Ar terminal
.Ar program
.Op Ar arguments ...
.Sh DESCRIPTION
.Nm
creates a new session and executes the specified
.Ar program
inside the session.
.Pp
The
.Ar terminal
argument is a path to a
.Xr tty 4
terminal device for the session, which is initialized to its default options (as
per
.Xr stty 1
.Sy sane ) ,
except the modem control settings are preserved in the
.Vt struct termios
.Fa c_cflag
field (except
.Dv CREAD )
as well as the
.Fa c_ispeed
and
.Fa c_ospeed
fields.
The
.Dv CREAD
bit is enabled in
.Vt struct termios
.Fa c_cflag
to enable receiving data on the terminal.
The terminal window size is unchanged.
.Pp
If the process is already a session leader, then the
.Ar program
is executed along with any optional
.Ar arguments .
Otherwise
.Nm
forks and makes the child a session leader, and the parent waits for the child
to exit.
.Pp
The options are as follows:
.Bl -tag -width "1234567890"
.It Fl 5
Receive 5 bits per word
.Dv ( CS5
in
.Fa c_cflag ) .
.It Fl 6
Receive 6 bits per word
.Dv ( CS6
in
.Fa c_cflag ) .
.It Fl 7
Receive 7 bits per word
.Dv ( CS7
in
.Fa c_cflag ) .
.It Fl 8
Receive 8 bits per word
.Dv ( CS8
in
.Fa c_cflag ) .
.It Fl b
Always fork and run the new session in the background without waiting for it to
exit.
.It Fl e
Enable even parity bits
.Dv ( PARENB
in
.Fa c_cflag ) .
.It Fl f
Forcefully take ownership of the terminal even if another session already owns
it.
.It Fl h Ar height
Set the terminal window rows to
.Ar height .
.It Fl l
Output the operating system logo before running the program.
.It Fl n
Disable parity bits
.Li ( ~ Ns Dv (PARENB | PARODD)
in
.Fa c_cflag ) .
.It Fl o
Enable odd parity bits
.Dv ( PARENB | PARODD
in
.Fa c_cflag ) .
.It Fl R
Disable receiving data
.Li ( ~ Ns Dv (CREAD)
in
.Fa c_cflag ) .
This option is useful to prevent a race condition where the user may type
.Sy ^C
or
.Sy ^\\
to send
.Dv SIGINT
or
.Dv SIGQUIT
before the program is ready to handle input.
.It Fl s Ar speed
Set the terminal input and output speeds to
.Ar speed .
.It Fl t Ar term
Set the
.Xr TERM
environment variable to
.Ar term .
.It Fl w Ar width
Set the terminal window columns to
.Ar width .
.El
.Sh EXIT STATUS
.Nm
exits as the
.Ar program
does on success and non-zero otherwise.
If
.Fl b ,
then
.Nm
exits 0 after forking the new session.
.Sh SEE ALSO
.Xr sh 1 ,
.Xr tcsetattr 2 ,
.Xr tcsetwinsize 2 ,
.Xr com 4 ,
.Xr tty 4 ,
.Xr kernel 7 ,
.Xr init 8 ,
.Xr login 8