LPD
Section: Maintenance Commands (8)
Updated: December 8, 1985
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NAME
lpd - 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 ALSO
lpc(8),
netinfo(5),
pac(8),
lpr(1),
lpq(1),
lprm(1),
syslog(3),
printcap(5)
Index
- NAME
-
- SYNOPSIS
-
- DESCRIPTION
-
- FILES
-
- SEE ALSO
-
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