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

# cups-backend(1)

cups backend transmission interfaces

## NAME

backend - cups backend transmission interfaces

## SYNOPSIS

**backend** job user title num-copies options \[ *filename* \]

## DESCRIPTION

The CUPS backend interface provides a standard method for sending document files to different physical interfaces.

Backends 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 if required by the physical interface.

The command name (argv\[0\]) is set to the device URI of the destination printer. Starting with CUPS 1.1.22, any authentication information in argv\[0\] will be removed, so backend developers are urged to use the DEVICE\_URI environment variable whenever authentication information is required.

## ENVIRONMENT VARIABLES

The following environment variables are defined by the CUPS server when executing the backend:

- 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; this is provided for shell scripts which may not be able to get the passed argv\[0\] string and for backends that require any authentication information which is not included in argv\[0\].

- LANG

  The default language locale (typically C or en).

- PATH

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

- PPD

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

- PRINTER

  The name of the printer.

- 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 backend, typically root; consult the cupsd.conf file for the current setting.

## SEE ALSO

[cupsd(8)](/cupsd/8.md), [filter(1)](/filter/1.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.