LPD(8) DG/UX 4.30 LPD(8)
NAME
lpd - line printer daemon
SYNOPSIS
/usr/lib/lpd [ -l ] [ port # ]
DESCRIPTION
Lpd is the line printer daemon (spool area handler) and is
normally invoked at boot time from the rc.lpsched file if
the system administrator has set the lpd_START variable in
/etc/dgux.params to true. The system administrator must
also set up printers in /etc/printcap. and the
corresponding spooling areas. Lpd then makes a single pass
through this 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. Finally the printer system maintains protected
spooling areas so that users cannot access queued files, but
the printer processes can. Thus the spooling areas setup by
the system administrator must have mode 660 with daemon user
and daemon group.
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 your favorite 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.
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LPD(8) DG/UX 4.30 LPD(8)
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 Standford).
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
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LPD(8) DG/UX 4.30 LPD(8)
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 to indent the output
by (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. 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 dg_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
/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), lpr(1), lpq(1), lprm(1), syslog(3),
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