filter(1)

NAME
filter - cups file conversion filter interfaces

SYNOPSIS
filter job user title num-copies options [ filename ]

DESCRIPTION
The CUPS filter interface provides a standard method for adding support for new document types to CUPS. Each filter is capable of converting from one or more input formats to another format that can either be printed directly or piped into another filter to get it to a printable format.

Filters must be capable of reading from a filename on the command-line or from the standard input, copying the standard input to a temporary file as required by the file format. All output must be sent to the standard output.

The command name (argv[0]) is set to the name of the destination printer.

ENVIRONMENT VARIABLES
The following environment variables are defined by the CUPS server when executing each filter:

CHARSET
    The default text character set (typically us-ascii or iso-8859-1).

CLASS
    When a job is submitted to a printer class, contains the name of the destination printer class. Otherwise this environment variable will not be set.

CONTENT_TYPE
    The MIME type associated with the file (e.g. application/postscript).

CUPS_DATADIR
    The directory where data files can be found.

CUPS_SERVERROOT
    The root directory of the server.

DEVICE_URI
    The device-uri associated with the printer.

LANG
    The default language locale (typically C or en).

PATH
    The standard execution path for external programs that may be run by the filter.

PPD
    The full pathname of the PostScript Printer Description (PPD) file for this printer.

PRINTER
    The name of the printer; this is provided for shell scripts which may not be able to get the passed argv[0] string.

RIP_CACHE
    The recommended amount of memory to use for Raster Image Processors (RIPs).

SOFTWARE
    The name and version number of the server (typically CUPS/1.1).

TZ
    The timezone of the server.

USER
    The user executing the filter (typically lp).

COMPATIBILITY
While the filter interface is compatible with System V interface scripts, it will only work with the System V interface script as the only filter. Typically the interface script will be provided via the lpadmin(8) command using the -i option.

SEE ALSO
backend(1), cupsd(8), CUPS Interface Design Description, CUPS Software Administrators Manual, CUPS Software Programmers Manual, http://localhost:631/documentation.html

COPYRIGHT
Copyright 1993-2003 by Easy Software Products, All Rights Reserved.