Manual page for LPD(8)
lpd - printer daemon
SYNOPSIS
/usr/lib/lpd
[
-l
] [
-L
logfile
] [
port#
]
DESCRIPTION
lpd
is the line printer daemon (spool area handler).
It is usually invoked at boot time from the
rc.8
script, making a single pass through the
printcap.5
file to find out about the existing printers and printing any files
left after a crash.
It then accepts requests to print files in a queue,
transfer files to a spooling area, display a queue's status, or remove
jobs from a queue.
In each case, it forks a child process
for each request, and continues to listen for subsequent requests.
The Internet port number used to communicate
with other processes is usually obtained with
getservent.3n
but can be specified with the
port#
argument.
If a file cannot be opened, an error message is logged using the
LOG_LPR
facility of
syslog.3
lpd
will try up to 20 times
to reopen a file it expects to be there, after which it proceeds
to the next file or job.
OPTIONS
- -l
-
Log valid requests received from the network.
This can be useful for debugging purposes.
- -L logfile
-
Change the file used for writing error conditions to
logfile.
The default is to report a message using the
syslog.3
facility.
OPERATION
Access Control
Access control is provided by two means.
First, all requests must come from
one of the machines listed in either the file
/etc/hosts.equiv
or
/etc/hosts.lpd.
(This latter file is in
hosts.equiv.5
format.)
Second, if the
rs
capability is specified in the
printcap
entry,
lpr.1
requests are only be honored for users with accounts on the
printer host.
Lock File
The
lock
file in each spool directory is used to prevent multiple daemons from
becoming active, and to store information about the daemon process for
lpr.1
lpq.1
and
lprm.1
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
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
Control Files
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
that indicates what to do with the remainder of the line.
-
- J
-
Job name to print on the burst page.
- C
-
Classification line on the burst page.
- L
-
Literal. This line contains identification information from
the password file, and causes a burst page to be printed.
- T
-
Title string for page headings printed by
pr.1v
- H
-
Hostname of the machine where
lpr.1
was invoked.
- P
-
Person. Login name of the person who invoked
lpr.1
This is used to verify ownership by
lprm.1
- M
-
Send mail to the specified user when the current print job completes.
- f
-
Formatted File, the name of a file to print that is already formatted.
- l
-
Like
f,
but passes control characters along, and does not make page breaks.
- p
-
Name of a file to print using
pr.1v
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
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 a 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.1v
and the text filters.
- I
-
Indent. Specify the number of characters
by which to indent the output.
- U
-
Unlink. The name of file to remove upon completion of printing.
- N
-
Filename. The name of the file being printed, or a blank
for the standard input (when
lpr.1
is invoked in a pipeline).
Data Files
When a file is spooled for printing,
the contents are copied into a data file
in the spool directory.
Data file names begin with
df.
When
lpr
is called with the
-s
option, the control files contain a symbolic link
to the actual file, and no data files are created.
Minfree File
The file
minfree
in each spool directory contains the
number of kilobytes to leave free
so that the line printer queue won't completely fill the disk.
FILES
- /etc/printcap
-
printer description file
- /var/spool/*
-
spool directories
- /var/spool/*/minfree
-
minimum free space to leave
- /dev/lp*
-
line printer devices
- /dev/printer
-
socket for local requests
- /etc/hosts.equiv
-
hosts allowed equivalent host access
- /etc/hosts.lpd
-
hosts allowed printer access only
SEE ALSO
lpq.1
lpr.1
lprm.1
hosts.5
hosts.equiv.5
printcap.5
lpc.8
pac.8
Created by unroff & hp-tools.
© somebody (See intro for details). All Rights Reserved.
Last modified 11/5/97