The printcap database is a simplified version of the termcap database for describing printers. The spooling system accesses the printcap file every time it's used, so you can dynamically add or remove printers. Each entry in the database describes one printer.
Note that you can't replace this database — as you can for termcap — because that might allow accounting to be bypassed.
The default printer is normally lp, although you can use the environment variable PRINTER to override this. Each spooling utility supports a -Pprinter option to explicitly name a destination printer.
Each entry in the printcap file describes a printer. An entry is a line consisting of a number of fields separated by : characters. The first entry for each printer gives the known names for the printer, separated by | characters.
The first name is conventionally a number. The second name is the most common abbreviation for the printer; the last name should be a long name fully identifying the printer. The second name should contain no blanks; the last name may well contain blanks for readability. Entries may continue onto multiple lines by giving a \ as the last character of a line. Empty fields may be included for readability.
Capabilities in printcap are all introduced by two-character codes and are of these types:
states that the remote printer is named spinwriter.
|af||Name of accounting file||String||NULL|
|br||If lp is a tty, set the baud rate (ioctl() call)||Numeric||None|
|cf||cifplot data filter||String||NULL|
|df||TeX data filter (DVI format)||String||NULL|
|du||Userid of user daemon||String||0|
|fc||If lp is a tty, clear flag bits||Numeric||0|
|ff||String to send for a form feed||String||\f|
|fo||Print a form feed when device is opened||Boolean||False|
|fs||Similar to fc but set bits||Numeric||0|
|gf||Graph data filter (plot(3X) format)||String||NULL|
|hl||Print the burst header page last||Boolean||False|
|ic||Driver supports (non standard) ioctl() to indent printout||Boolean||False|
|if||Name of input/communication filter (created per job)||String||NULL|
|lf||Error logging filename||String||/dev/console|
|lo||Name of lock file||String||lock|
|lp||Device name to open for output||String||/dev/lp|
|mc||Maximum number of copies||Numeric||0|
|ms||List of terminal modes to set or clear||String||NULL|
|mx||Maximum file size (in BUFSIZ blocks); zero = unlimited||Numeric||1000|
|nf||ditroff data filter (device independent troff)||String||NULL|
|of||Name of output/banner filter (created once)||String||NULL|
|pc||Price per foot or page in hundredths of cents||Numeric||200|
|pl||Page length (in lines)||Numeric||66|
|pw||Page width (in characters)||Numeric||132|
|px||Page width in pixels (horizontal)||Numeric||0|
|py||Page length in pixels (vertical)||Numeric||0|
|rf||Filter for printing FORTRAN style text files||String||NULL|
|rg||Restricted group — only members of group allowed access||String||NULL|
|rm||Machine name for remote printer||String||NULL|
|rp||Remote printer name argument||String||lp|
|rs||Restrict remote users to those with local accounts||Boolean||False|
|rw||Open printer device read/write instead of write-only||Boolean||False|
|sb||Short banner (one line only)||Boolean||False|
|sc||Suppress multiple copies||Boolean||False|
|sf||Suppress form feeds||Boolean||False|
|sh||Suppress printing of burst page header||Boolean||False|
|tc||Name of similar printer; must be last||String||NULL|
|tf||troff data filter (C/A/T phototypesetter)||String||NULL|
|tr||Trailer string to print when queue empties||String||NULL|
|vf||Raster image filter||String||NULL|
|xc||If lp is a tty, clear local mode bits||Numeric||0|
|xs||Like xc but set bits||Numeric||0|
If the local line printer driver supports indentation, the daemon must understand how to invoke it.
Note that the fs, fc, xs, and xc fields are flag masks rather than values. Certain default device flags are set when the device is opened by the line printer daemon if the device is connected to a terminal port. The flags indicated in the fc field are then cleared; the flags in the fs field are then set (or vice versa, depending on the order of fc#nnnn and fs#nnnn in the /etc/printcap file).
The bits cleared by the fc field and set by the fs field are those in the sg_flags field of the sgtty structure, as set by the TIOCSETP ioctl() call, and the bits cleared by the xc field and set by the xs field are those in the “local flags” word, as set by the TIOCLSET ioctl() call. See <sys/termio.h> for a description of these flags.
For example, to set exactly the flags 06300 in the fs field, which specifies that the EVENP, ODDP, and XTABS modes are to be set and that all other flags are to be cleared, do:
The same process applies to the xc and xs fields. Alternatively, you can use the ms field to specify modes to be set and cleared. These modes are specified as stty modes; you can specify any mode supported by stty, except for the baud rate (which you must specify with the br field).
For example, to set the terminal port (to which the printer is attached) to even parity, TAB expansion, no NEWLINE to RETURN/LINEFEED translation, and RTS/CTS flow control enabled, do the following:
The tc field must appear last in the list of capabilities. Each type of printer should have a general entry describing common capabilities. Then an individual printer can be defined with its particular capabilities, plus a tc field that points to the general entry for that type of printer.
For information about setting up the printcap file, see the Printing chapter of the Neutrino User's Guide.
lpd, lpr, lprc, lprq, lprrm
Printing chapter of the Neutrino User's Guide