lpd(1M) DG/UX R4.11MU05 lpd(1M)
NAME
lpd - line printer spooler
SYNOPSIS
/usr/lib/lpd [ -l ] [ port# ]
DESCRIPTION
Lpd is the line printer spool area handler (daemon) 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(3N) 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.
Note that by default the AT&T lpsched(1M) BSD emulation is listening
to the BSD printer network port. If you desire to use the BSD lpd,
you must delete the Port Services entry for this emulation mode.
This can be accomplished through sysadm(1M) with the sequence Device
-> Port -> Port Service -> Delete -> tcp -> lpd. The original
settings can be found in /etc/saf/tcp/_pmtab.proto.
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 spooler user and spooler 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
spoolers from becoming active simultaneously, and to store
information about the spooler process for lpr(1), lpq(1), and
lprm(1). After the spooler 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
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 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(3C)
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(3C) to provide exclusive access to the lock file
and to prevent multiple spoolers from becoming active simultaneously.
If the spooler 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 spooler
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
lpq(1), lpr(1), lprm(1); lpc(1M); syslog(3C).
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