V7addenda/lpd.8

.TH LPD 8 
.SH NAME
lpd \- line printer daemon
.SH SYNOPSIS
.B /etc/lpd
.SH DESCRIPTION
.I Lpd
is the daemon for the line printer.
.I Lpd
uses the directory
.IR /usr/spool/lpd .
The file
.I lock
in that directory is used
to prevent two daemons from becoming active.
After the program has successfully set the lock,
it forks and the main path exits, thus
spawning the daemon.
The directory is scanned for files
beginning with
.B df.
Each such file is submitted as a job.
Each line of a job file must begin with a key
character to specify what to do with the remainder
of the line.
.TP 5
.B  L
specifies that the remainder of the line is to
be sent as a literal.
.TP 5
.B  B
specifies that the rest of the line
is a file name.
.TP 5
.B  F
is the same as
.B B
except a form feed is prepended to the file.
.TP 5
.B  U
specifies that the rest of the line
is a file name.
After the job has been transmitted,
the file is unlinked.
.TP 5
.B  M
is followed by a user ID; after the job is sent,
a message is
mailed to the user via the
.IR mail (1)
command
to verify the sending of the job.
.PP
Any error encountered will cause the daemon to
wait and start over.
This means that an improperly constructed
.B df
file may cause the same job to be submitted
repeatedly.
.PP
.I Lpd
is automatically initiated by the line printer command,
.I lpr.
.PP
.PP
To restart
.I lpd
(in the case of hardware or software malfunction),
it is necessary to first kill the old
daemon
(if still alive),
and remove the lock file
before initiating
the new daemon.
This is done automatically when the system is brought up,
by
.I /etc/rc,
in case there were any jobs left in the spooling directory
when the system last went down.
.SH FILES
/usr/spool/lpd/*
spool area for line printer daemon
.br
/etc/passwd
to get the user's name
.br
/dev/lp
line printer device
.SH "SEE ALSO"
lpr(1)