LPD(8) BSD LPD(8)
NAME
lpd - line printer daemon
SYNOPSIS
/usr/lib/lpd [ -l ] [ port# ]
DESCRIPTION
lpd is the line printer daemon (spool area handler). It is normally
invoked at boot time from the rc(8) file. It makes a single pass through
the printcap(5) file to find out about the existing printers, and prints
any files left after a crash. It then uses the system calls listen(2) and
accept(2) 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. The Internet port number used to
rendezvous with other processes is normally obtained with
getservbyname(3) but can be changed with the port# argument.
Access control is provided by two means. First, all requests must come
from one of the machines listed in the file /etc/hosts.equiv or
/etc/hosts.lpd. Second, if the "rs" capability is specified in the
printcap entry for the printer being accessed, lpr requests will only be
honored for those users with accounts on the machine with the printer.
The file named minfree 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. The minfree file can be edited with your favorite text
editor.
The file named lock in each spool directory is used to prevent multiple
daemons from becoming active simultaneously, and to store information
about the daemon process for lpr(1), lpq(1), and lprm(1). After the
daemon has successfully set the lock, it scans the directory for files
beginning with cf. Lines in each cf 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 (see "KEY
CHARACTERS", below).
If lpd can't open a file, it logs a message via syslog(3) using the
LOG_LPR facility. lpd will try up to 20 times to reopen a file it
expects to be there, after which it will skip the file to be printed.
lpd uses flock(2) 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 ASCII form and contains two
lines. The first is the process id of the daemon and the second is the
control filename of the current job being printed. The second line is
updated to reflect the current status of lpd for the programs lpq(1) and
lprm(1).
OPTIONS
port# Change the Internet port number used to rendezvous with other
processes to port#.
-l Log valid requests received from the network. This option can
be useful for debugging purposes.
KEY CHARACTERS
J Job Name. A string to be used for the job name on the burst
page.
C Classification. A string to be used for the classification
line on the burst page.
L Literal. The line contains identification information from the
password file, and causes the banner page to be printed.
T Title. A string to be used as the title for pr(1).
H Host Name. The name of the machine where lpr was invoked.
P Person. The login name of the person who invoked lpr. This is
used to verify ownership by lprm.
M Send mail to the specified user when the current print job
completes.
f Formatted File. The name of a file to print which is already
formatted.
l Like f, but passes control characters and does not make page
breaks.
p The name of a file to print using pr(1) as a filter.
t troff File. The file contains troff(1) output (phototypesetter
commands).
n Ditroff File. The file contains device independent troff
output.
d DVI File. The file contains Tex(l) output (DVI format from
Stanford).
g Graph File. The file contains data produced by plot(3X).
c Cifplot File. The file contains data produced by cifplot.
v The file contains a raster image.
r The file contains text data with FORTRAN carriage control
characters.
1 troff Font R. The name of the font file to use instead of the
default.
2 troff Font I. The name of the font file to use instead of the
default.
3 troff Font B. The name of the font file to use instead of the
default.
4 troff Font S. The name of the font file to use instead of the
default.
W Width. Changes the page width (in characters) used by pr(1) and
the text filters.
I Indent. The number of characters to indent the output by (in
ascii).
U Unlink. The name of a file to remove upon completion of
printing.
N Filename. The name of the file which is being printed, or a
blank for the standard input (when lpr is invoked in a
pipeline).
FILES
/etc/printcap printer description file
/usr/spool/lpd spool directories
/usr/spool/lpd/minfree minimum free space to leave
/usr/spool/lpd/servername hostname of the machine to run lpd
/dev/lp* line printer devices
/dev/printer socket for local requests
/etc/hosts.equiv lists machine names allowed printer access
/etc/hosts.lpd lists machine names allowed printer access,
but not under same administrative control.
SEE ALSO
llbd(8), lpc(8), lpr(1), lpq(1), lprm(1), syslog(3), printcap(5)