LPD(8)							      System Manager's Manual							    LPD(8)

NAME

       lpd - line printer daemon

SYNOPSIS

       /usr/sbin/lpd [ -l ] [ port # ]

DESCRIPTION

       Lpd  is	the  line  printer  daemon  (spool area handler) and 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 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.

       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(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 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  con-
       tains  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), pac(1), lpr(1), lpq(1), lprm(1), syslog(3), printcap(5)
       4.2BSD Line Printer Spooler Manual

4.2 Berkeley Distribution					 October 23, 1996							    LPD(8)