---
name: "cups-filter"
section: "1"
platform: "linux"
package: "cupsys"
version: "1.1.23-10sarge1"
release: "Debian 3.1 (Sarge)"
platforms: ["linux"]
url: "https://new.carta.tech/cups-filter"
---

# cups-filter(1)

cups file conversion filter interfaces

## 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; consult the cupsd.conf file for the current setting.

## 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)](/lpadmin/8.md)** command using the *-i* option.

## SEE ALSO

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

## COPYRIGHT

Copyright 1993-2005 by Easy Software Products, All Rights Reserved.