LPD(8) 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 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 _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 dae‐ mons 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 classification line on the burst page. L Literal. The line contains identification info from the pass‐ word 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 com‐ pletes. f Formatted File. Name of a file to print which is already for‐ matted. 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 phototype‐ setter commands). n Ditroff File. The file contains device independent troff out‐ put. 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 control char‐ acters. 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 _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 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 _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 4.2 Berkeley Distribution December 8, 1985 LPD(8)