1LPD(8) System Manager's Manual LPD(8)
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6 lpd - line printer daemon
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9 /usr/sbin/lpd [ -l ] [ port # ]
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12 Lpd is the line printer daemon (spool area handler) and is normally
13 invoked at boot time from the rc(8) file. It makes a single pass
14 through the printcap(5) file to find out about the existing printers
15 and prints any files left after a crash. It then uses the system calls
16 listen(2) and accept(2) to receive requests to print files in the
17 queue, transfer files to the spooling area, display the queue, or
18 remove jobs from the queue. In each case, it forks a child to handle
19 the request so the parent can continue to listen for more requests.
20 The Internet port number used to rendezvous with other processes is
21 normally obtained with getservbyname(3) but can be changed with the
22 port# argument. The -l flag causes lpd to log valid requests received
23 from the network. This can be useful for debugging purposes.
24 Access control is provided by two means. First, All requests must come
26 from one of the machines listed in the file /etc/hosts.equiv or
27 /etc/hosts.lpd. Second, if the ``rs'' capability is specified in the
28 printcap entry for the printer being accessed, lpr requests will only
29 be honored for those users with accounts on the machine with the
30 printer.
31 The file minfree in each spool directory contains the number of disk
33 blocks to leave free so that the line printer queue won't completely
34 fill the disk. The minfree file can be edited with your favorite text
35 editor.
36 The file lock in each spool directory is used to prevent multiple dae‐
38 mons from becoming active simultaneously, and to store information
39 about the daemon process for lpr(1), lpq(1), and lprm(1). After the
40 daemon has successfully set the lock, it scans the directory for files
41 beginning with cf. Lines in each cf file specify files to be printed
42 or non-printing actions to be performed. Each such line begins with a
43 key character to specify what to do with the remainder of the line.
44 J Job Name. String to be used for the job name on the burst page.
46 C Classification. String to be used for the classification line
48 on the burst page.
49 L Literal. The line contains identification info from the pass‐
51 word file and causes the banner page to be printed.
52 T Title. String to be used as the title for pr(1).
54 H Host Name. Name of the machine where lpr was invoked.
56 P Person. Login name of the person who invoked lpr. This is used
58 to verify ownership by lprm.
59 M Send mail to the specified user when the current print job com‐
61 pletes.
62 f Formatted File. Name of a file to print which is already for‐
64 matted.
65 l Like ``f'' but passes control characters and does not make page
67 breaks.
68 p Name of a file to print using pr(1) as a filter.
70 t Troff File. The file contains troff(1) output (cat phototype‐
72 setter commands).
73 n Ditroff File. The file contains device independent troff out‐
75 put.
76 d DVI File. The file contains Tex(l) output (DVI format from
78 Standford).
79 g Graph File. The file contains data produced by plot(3X).
81 c Cifplot File. The file contains data produced by cifplot.
83 v The file contains a raster image.
85 r The file contains text data with FORTRAN carriage control char‐
87 acters.
88 1 Troff Font R. Name of the font file to use instead of the
90 default.
91 2 Troff Font I. Name of the font file to use instead of the
93 default.
94 3 Troff Font B. Name of the font file to use instead of the
96 default.
97 4 Troff Font S. Name of the font file to use instead of the
99 default.
100 W Width. Changes the page width (in characters) used by pr(1) and
102 the text filters.
103 I Indent. The number of characters to indent the output by (in
105 ascii).
106 U Unlink. Name of file to remove upon completion of printing.
108 N File name. The name of the file which is being printed, or a
110 blank for the standard input (when lpr is invoked in a pipe‐
111 line).
112 If a file can not be opened, a message will be logged via syslog(3)
114 using the LOG_LPR facility. Lpd will try up to 20 times to reopen a
115 file it expects to be there, after which it will skip the file to be
116 printed.
117 Lpd uses flock(2) to provide exclusive access to the lock file and to
119 prevent multiple deamons from becoming active simultaneously. If the
120 daemon should be killed or die unexpectedly, the lock file need not be
121 removed. The lock file is kept in a readable ASCII form and contains
122 two lines. The first is the process id of the daemon and the second is
123 the control file name of the current job being printed. The second
124 line is updated to reflect the current status of lpd for the programs
125 lpq(1) and lprm(1).
126
128 /etc/printcap printer description file
129 /usr/spool/* spool directories
130 /usr/spool/*/minfree minimum free space to leave
131 /dev/lp* line printer devices
132 /dev/printer socket for local requests
133 /etc/hosts.equiv lists machine names allowed printer access
134 /etc/hosts.lpd lists machine names allowed printer access,
135 but not under same administrative control.
136
138 lpc(8), pac(1), lpr(1), lpq(1), lprm(1), syslog(3), printcap(5)
139 4.2BSD Line Printer Spooler Manual
1404.2 Berkeley Distribution October 23, 1996 LPD(8)