magicfilter(8) -- Linux man page



magicfilter - automatic configurable printer filter  


magicfilter ifdef(`HAVE_XGETOPT', config-file [-c] [-n user] [-h host] [-iindent] [--debug] [other-options], config-file [-c] [-n user] [-h host] [-iindent] [other.options])  


magicfilter is an extensible and customizable automatic printer filter. It selects an appropriate conversion technique for the input data by seeking for magic numbers, and then utilizing the appropriate conversion utility.

magicfilter is primarily intended for use as the ``input filter'' by the lpd print spooler. The options accepted by magicfilter are exactly the ones passed to the input filter by lpd.  


Typically magicfilter will be invoked by lpd and hence provided the right options automatically. This list is included for reference only.
Copy the input to the output without any conversion whatsoever (used by lpd whenever the -l option is passed to the lpr program).
The login name of the user who submitted the job. Available to subfilters as $LPUSER. If the user has an associated GECOS entry it will be available as $LPUSERNAME.
The host on which the job was submitted. Available to subfilters as $LPHOST.
A numeric option passed by lpd; can be set by the user by the -i option to lpr. Although nominally used for the amount of indentation requested, magicfilter makes it available to subfilters for any useful purpose as $LPINDENT.
LPRng class (priority) name. Available to subfilters as $LPCLASS.
Format letter (passed by LPRng only). When used as input filter (if) this will be f, when used as other filter types it will be the option character corresponding to this filter. Available to subfilters as $LPFORMAT.
The name of the printer job (passed by LPRng only). Available to subfilters as $LPJOB.
Copy count (passed by LPRng only). Available to subfilters as $LPCOPIES.
User name from the banner page (passed by LPRng only). Available to subfilters as $BANNERNAME.
Printer name (passed by LPRng only). Available to subfilters as $PRINTER.
Spool queue name (passed by LPRng only). Available to subfilters as $LPQUEUE.
Accounting information (passed by LPRng only). Available to subfilters as $LPACCT.
LPRng ``Z-options''. The LPRng lpr program supports a -Z option, which can be used to pass arbitrary information to the printer filters. Available to subfilters as $ZOPT. ifdef(`HAVE_XGETOPT',
Write debugging output to stdout. Every --debug increases the quantity of debugging output. ifelse(magicfilter,`magicfilter-t',,
Write the default magicfilter configuration to stdout. This can be customised and put in @confdir@/ if you wish to modify which filetypes magicfilter knows about.)
Prints out a synopsis of the command-line switches supported.,)
other options
Any other options, such as the -w, -l, -x, and -y options typically passed by lpd are ignored.


To run magicfilter from lpd it should be entered as one of the filters in the /etc/printcap file. Typically, it will be the input filter (if). Since most version of lpd do not accept arguments entered as part of the filter name, typically the filter name entered into the /etc/printcap file will simply be the name of the configuration file, which is set executable and starts with the line:

#! @exedir@/magicfilter

Most UNIX kernels will then be able to treat the configuration file itself as if it was the actual program.

For systems which do not support the ``#!-hack'', the filter set in the if entry should point to magicfilter directly, and the accounting file (af) entry should point to the configuration file. This, however, is a less general, and hence less desirable solution.

This version of magicfilter supports the enhanced lpd included with the LPRng package from  


Magicfilter has been extensively modified for the 2.0 release, and has very little in common with the old 1.2 magicfilter. The config-file format has changed pretty drastically, and old config files will not work anymore.

Currently, there is no protection against the pipe or fpipe facilities going into an infinite loop.



H. Peter Anvin <>, David Parsons <>  


printcap(5), magicfilter(5), ifelse(magicfilter,magicfilter-t,.BR magicfilter (5)`,' ,)dnl lpr(8), dvips(1), grog(1), gs(1), gzip(1), troff(1).