LPD(8)LPD(8)NAMElpd - line printer daemon
SYNOPSIS
/usr/lib/lpd [ -l ] [ port # ]
DESCRIPTION
The lpd line printer daemon (spool area handler) 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. The
-l flag causes lpd to log valid requests received from the network.
This can be useful for debugging purposes.
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 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 a text editor.
The file 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.
J Job Name. String to be used for the job name on the burst page.
C Classification. String to be used for the classification line
on the burst page.
L Literal. The line contains identification info from the
password file, and causes the banner page to be printed.
T Title. String to be used as the title for pr(1).
H Host Name. Name of the machine where lpr was invoked.
P Person. 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. Name of a file to print which is already
formatted.
l Like ``f'', but passes control characters and does not make page
breaks.
p Name of a file to print using pr(1) as a filter.
t Troff File. The file contains troff(1) output (cat
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. Name of the font file to use instead of the
default.
2 Troff Font I. Name of the font file to use instead of the
default.
3 Troff Font B. Name of the font file to use instead of the
default.
4 Troff Font S. 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 with which to indent the
output (in ascii).
U Unlink. Name of file to remove upon completion of printing.
N File name. The name of the file which is being printed, or a
blank for the standard input (when lpr is invoked in a
pipeline).
If a file can not be opened, a message will be logged via syslog(3)
using the LOG_LPR facility. The lpd daemon 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.
The lpd daemon uses flock(2) to provide exclusive access to the lock
file and to prevent multiple deamons 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 file name 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).
FILES
/etc/printcap printer description file - if NetInfo is not running.
/usr/spool/* spool directories
/usr/spool/*/minfree minimum free space to leave
/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 ALSOlpc(8), netinfo(5), pac(8), lpr(1), lpq(1), lprm(1), syslog(3),
printcap(5)4.2 Berkeley Distribution December 8, 1985 LPD(8)