4.3BSD-UWisc/man/cat8/lpd.8
LPD(8) UNIX Programmer's Manual LPD(8)
NAME
lpd - line printer daemon
SYNOPSIS
/usr/lib/lpd [ -l ] [ port # ]
DESCRIPTION
_L_p_d is the line printer daemon (spool area handler) and is
normally invoked at boot time from the _r_c(8) file. It makes
a single pass through the _p_r_i_n_t_c_a_p(5) file to find out about
the existing printers and prints any files left after a
crash. It then uses the system calls _l_i_s_t_e_n(2) and _a_c_c_e_p_t(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 han-
dle 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 _g_e_t_-
_s_e_r_v_b_y_n_a_m_e(3) but can be changed with the _p_o_r_t# argument.
The -l flag causes _l_p_d 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
/_e_t_c/_h_o_s_t_s._e_q_u_i_v or /_e_t_c/_h_o_s_t_s._l_p_d. Second, if the ``rs''
capability is specified in the _p_r_i_n_t_c_a_p entry for the
printer being accessed, _l_p_r requests will only be honored
for those users with accounts on the machine with the
printer.
The file _m_i_n_f_r_e_e 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 _m_i_n_f_r_e_e file can be
edited with your favorite text editor.
The file _l_o_c_k in each spool directory is used to prevent
multiple daemons from becoming active simultaneously, and to
store information about the daemon process for _l_p_r(1),
_l_p_q(1), and _l_p_r_m(1). After the daemon has successfully set
the lock, it scans the directory for files beginning with
_c_f. Lines in each _c_f 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 classifica-
tion line on the burst page.
L Literal. The line contains identification info from
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LPD(8) UNIX Programmer's Manual LPD(8)
the password file and causes the banner page to be
printed.
T Title. String to be used as the title for _p_r(1).
H Host Name. Name of the machine where _l_p_r was invoked.
P Person. Login name of the person who invoked _l_p_r.
This is used to verify ownership by _l_p_r_m.
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 _p_r(1) as a filter.
t Troff File. The file contains _t_r_o_f_f(1) output (cat
phototypesetter commands).
n Ditroff File. The file contains device independent
troff output.
d DVI File. The file contains _T_e_x(l) output (DVI format
from Standford).
g Graph File. The file contains data produced by
_p_l_o_t(3X).
c Cifplot File. The file contains data produced by _c_i_f_-
_p_l_o_t.
v The file contains a raster image.
r The file contains text data with FORTRAN carriage con-
trol 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.
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LPD(8) UNIX Programmer's Manual LPD(8)
W Width. Changes the page width (in characters) used by
_p_r(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 _l_p_r is
invoked in a pipeline).
If a file can not be opened, a message will be logged via
_s_y_s_l_o_g(3) using the _L_O_G__L_P_R facility. _L_p_d 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.
_L_p_d uses _f_l_o_c_k(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 unex-
pectedly, 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 _l_p_d
for the programs _l_p_q(1) and _l_p_r_m(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._2_B_S_D _L_i_n_e _P_r_i_n_t_e_r _S_p_o_o_l_e_r _M_a_n_u_a_l
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