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

NAME
     lpd - line printer spooler daemon

SYNOPSIS
     lpd [-l] [port#]

DESCRIPTION
     Lpd is the line printer daemon (spool area handler) and is normally in-
     voked 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.

     Available options:

     -l      The -l flag causes lpd to log valid requests received from the
             network. This can be useful for debugging purposes.

     port#   The Internet port number used to rendezvous with other processes
             is normally obtained with getservbyname(3) but can be changed
             with the port# argument.

     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 daemon begins processing files after it has successfully set the lock
     for exclusive access (descibed a bit later), and scans the spool directo-
     ry 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 com-
             pletes.

     f       Formatted File.  Name of a file to print which is already format-
             ted.

     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 phototypeset-
             ter commands).

     n       Ditroff File.  The file contains device independent troff output.

     r       DVI File.  The file contains Tex l output DVI format from Stand-
             ford).

     g       Graph File.  The file contains data produced by plot(3).

     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 charac-
             ters.

     1       Troff Font R. Name of the font file to use instead of the de-
             fault.

     2       Troff Font I. Name of the font file to use instead of the de-
             fault.

     3       Troff Font B. Name of the font file to use instead of the de-
             fault.

     4       Troff Font S. Name of the font file to use instead of the de-
             fault.

     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 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
     /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      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)

     4.2 BSD Line Printer Spooler Manual.

HISTORY
     An lpd daemon appeared in Version 6 AT&T UNIX.

4.2 Berkeley Distribution       March 16, 1991                               1