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.\" @(#)lpd.8 8.3 (Berkeley) 4/19/94
.Nd line printer spooler daemon
is the line printer daemon (spool area handler) and is normally invoked
file. It makes a single pass through the
file to find out about the existing printers and
prints any files left after a crash. It then uses the system calls
to receive requests to print files in the queue,
transfer files to the spooling area, display the queue,
or remove jobs from the queue. In each case, it forks a child to handle
the request so the parent can continue to listen for more requests.
to log valid requests received from the network. This can be useful
The Internet port number used to rendezvous
with other processes is normally obtained with
but can be changed with the
Access control is provided by two means. First, all requests must come from
one of the machines listed in the file
capability is specified in the
entry for the printer being accessed,
requests will only be honored for those users with accounts on the
machine with the printer.
in each spool directory contains the number of disk blocks to leave free
so that the line printer queue won't completely fill the disk.
file can be edited with your favorite text editor.
The daemon begins processing files
after it has successfully set the lock for exclusive
access (described a bit later),
and scans the spool directory
file specify files to be printed or non-printing actions to be
performed. Each such line begins with a key character
to specify what to do with the remainder of the line.
Job Name. String to be used for the job name on the burst page.
Classification. String to be used for the classification line
Literal. The line contains identification info from
the password file and causes the banner page to be printed.
Title. String to be used as the title for
Host Name. Name of the machine where
Person. Login name of the person who invoked
This is used to verify ownership by
Send mail to the specified user when the current print job completes.
Formatted File. Name of a file to print which is already formatted.
Like ``f'' but passes control characters and does not make page breaks.
Name of a file to print using
Troff File. The file contains
output (cat phototypesetter commands).
Ditroff File. The file contains device independent troff
DVI File. The file contains
DVI format from Standford.
Graph File. The file contains data produced by
Cifplot File. The file contains data produced by
The file contains a raster image.
The file contains text data with
FORTRAN carriage control characters.
Troff Font R. Name of the font file to use instead of the default.
Troff Font I. Name of the font file to use instead of the default.
Troff Font B. Name of the font file to use instead of the default.
Troff Font S. Name of the font file to use instead of the default.
Width. Changes the page width (in characters) used by
Indent. The number of characters to indent the output by (in ascii).
Unlink. Name of file to remove upon completion of printing.
File name. The name of the file which is being printed, or a blank
for the standard input (when
is invoked in a pipeline).
If a file cannot be opened, a message will be logged via
to reopen a file it expects to be there, after which it will
skip the file to be printed.
to provide exclusive access to the lock file and to prevent multiple
daemons from becoming active simultaneously. If the daemon should be killed
or die unexpectedly, the lock file need not be removed.
The lock file is kept in a readable
The first is the process id of the daemon and the second is the control
file name of the current job being printed. The second line is updated to
reflect the current status of
.Bl -tag -width "/var/spool/*/minfree" -compact
.It Pa /var/spool/*/minfree
minimum free space to leave
socket for local requests
lists machine names allowed printer access
lists machine names allowed printer access,
but not under same administrative control.
.%T "4.2 BSD Line Printer Spooler Manual"
daemon appeared in Version 6 AT&T UNIX.