.TH LPD 8
.UC
.SH NAME
lpd \- line printer daemon
.SH SYNTAX
.B /usr/lib/lpd
.br
.B /usr/lib/vpd
.SH DESCRIPTION
.I Lpd
is the line printer for the daemon.
.I Vpd 
is the Versatec printer/plotter daemon.
.I Lpd
uses the directory
.IR /usr/spool/lpd
(or
.IR /usr/spool/vpd
in the case of the vpd).
A file named 
.I lock
in that directory
prevents 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 spool directory is scanned for files
beginning with
.IR 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 will cause the daemon to
wait and start over.
Because of this, an improperly constructed
.I df
file may cause the same job to be submitted
repeatedly.
.PP
\fILpd\fP is automatically initiated by the line printer command, \fIlpr\fP.  
Similarily \fIvpd\fP is started by the command \fIvpr\fP.
.PP
To restart \fIlpd\fP (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 \fI/etc/rc\fP, in case there were any jobs left in the spooling
directory when the system went down last.
.SH FILES
.ta 2i
/usr/spool/lpd	spooling area for line printer daemon
.br
/usr/spool/vpd	spooling area for Versetec daemon
.br
/usr/spool/lpd/lock	lock file for line printer daemon
.br
/usr/spool/vpd/lock	lock file for Versatec daemon
.br
/etc/passwd	to get the user's name for banner
.br
/etc/group	to get the user's group name
.br
/dev/lp	line printer device
.br
/dev/vp0	Versetec printer/plotter device
.SH "SEE ALSO"
lpr(1), vpr(1)