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

     lpd — line printer spooler daemon

     lpd [-cdlpsW46] [port#]

     The lpd utility 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.

     Available options:

     -c      By default, if some remote host has a connection error while trying
             to send a print request to lpd on a local host, lpd will only send
             error message to that remote host.  The -c flag causes lpd to also
             log all of those connection errors via syslog(3).

     -d      Turn on SO_DEBUG on the Internet listening socket (see

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

     -p      The -p flag is a synonym for the -s flag.  It is being deprecated,
             and may be removed in a future version of lpd.

     -s      The -s (secure) flag causes lpd not to open an Internet listening
             socket.  This means that lpd will not accept any connections from
             any remote hosts, although it will still accept print requests from
             all local users.

     -W      By default, the lpd daemon will only accept connections which
             originate from a reserved-port (<1024) on the remote host.  The -W
             flag causes lpd to accept connections coming from any port.  This
             is can be useful when you want to accept print jobs from certain
             implementations of lpr written for Windows.

     -4      Inet only.

     -6      Inet6 only.

     -46     Inet and inet6 (default).

     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(5) 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 kilobytes
     to leave free so that the line printer queue will not 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 (described a bit later), and scans the spool 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(1) was invoked.

     P       Person.  Login name of the person who invoked lpr(1).  This is used
             to verify ownership by lprm(1).

     M       Send mail to the specified user when the current print job

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

     l       Like ``f'' but passes control characters and does not make page

     p       Name of a file to print using pr(1) as a filter.

     t       Troff File.  The file contains troff(1) output (cat phototypesetter

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

     r       DVI File.  The file contains Tex l output DVI format from Stanford.

     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

     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

     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(1) is invoked in a pipeline).

     Z       Locale.  String to be used as the locale for pr(1).

     If a file cannot be opened, a message will be logged via syslog(3) using
     the LOG_LPR facility.  The lpd utility will try up to 20 times to reopen a
     file it expects to be there, after which it will skip the file to be

     The lpd utility uses flock(2) to provide exclusive access to the lock file
     and to prevent multiple daemons 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

     /etc/printcap         printer description file
     /var/spool/*          spool directories
     /var/spool/*/minfree  minimum free space to leave
     /dev/lp*              line printer devices
     /var/run/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.

     lpq(1), lpr(1), lprm(1), setsockopt(2), syslog(3), hosts.lpd(5),
     printcap(5), chkprintcap(8), lpc(8), pac(8)

     4.2 BSD Line Printer Spooler Manual.

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

                                  June 6, 2001