Debian packages' master control file format
Each Debian package contains the master `control' file, which contains a number of fields, or comments when the line starts with '#'. Each field begins with a tag, such as Package or Version (case insensitive), followed by a colon, and the body of the field. Fields are delimited only by field tags. In other words, field text may be multiple lines in length, but the installation tools will generally join lines when processing the body of the field (except in the case of the Description field, see below).
The value of this field determines the package name, and is used to generate file names by most installation tools.
Typically, this is the original package's version number in whatever form the program's author uses. It may also include a Debian revision number (for non-native packages). The exact format and sorting algorithm are described in deb-version(5).
Should be in the format `Joe Bloggs <[email protected]>', and is typically the person who created the package, as opposed to the author of the software that was packaged.
The format for the package description is a short brief summary on the first line (after the "Description" field). The following lines should be used as a longer, more detailed description. Each line of the long description must be preceded by a space, and blank lines in the long description must contain a single '.' following the preceding space.
This is a general field that gives the package a category based on the software that it installs. Some common sections are `utils', `net', `mail', `text', `x11' etc.
Sets the importance of this package in relation to the system as a whole. Common priorities are `required', `standard', `optional', `extra' etc.
In Debian, the Section and Priority fields have a defined set of accepted values based on the Policy Manual. A list of these values can be obtained from the latest version of the debian-policy package.
This field is usually only needed when the answer is yes. It denotes a package that is required for proper operation of the system. Dpkg or any other installation tool will not allow an Essential package to be removed (at least not without using one of the force options).
The architecture specifies which type of hardware this package was compiled for. Common architectures are `i386', `m68k', `sparc', `alpha', `powerpc' etc. Note that the all option is meant for packages that are architecture independent. Some examples of this are shell and Perl scripts, and documentation.
The name of the distribution this package is originating from.
The url of the bug tracking system for this package. The current used format is bts-type://bts-address, like debbugs://bugs.debian.org.
The upstream project home page url.
List of tags describing the qualities of the package. The description and list of supported tags can be found in the debtags package.
This field is used to indicate how this package should behave on a multi-arch installations. The value same means that the package is co-installable with itself, but it must not be used to satisfy the dependency of any package of a different architecture from itself. The value foreign means that the package is not co-installable with itself, but should be allowed to satisfy the dependency of a package of a different arch from itself. The value allowed allows reverse-dependencies to indicate in their Depends field that they accept a package from a foreign architecture, but has no effect otherwise. The value no is the default when the field is omitted, in which case adding the field with an explicit no value is generally not needed.
The name of the source package that this binary package came from, if different than the name of the package itself.
Subarchitecture: value Kernel-Version: value Installer-Menu-Item: value
These fields are used by the debian-installer and are usually not needed. See /usr/share/doc/debian-installer/devel/modules.txt from the debian-installer package for more details about them.
List of packages that are required for this package to provide a non-trivial amount of functionality. The package maintenance software will not allow a package to be installed if the packages listed in its Depends field aren't installed (at least not without using the force options). In an installation, the postinst scripts of packages listed in Depends: fields are run before those of the packages which depend on them. On the opposite, in a removal, the prerm script of a package is run before those of the packages listed in its Depends: field.
List of packages that must be installed and configured before this one can be installed. This is usually used in the case where this package requires another package for running its preinst script.
Lists packages that would be found together with this one in all but unusual installations. The package maintenance software will warn the user if they install a package without those listed in its Recommends field.
Lists packages that are related to this one and can perhaps enhance its usefulness, but without which installing this package is perfectly reasonable.
The syntax of Depends, Pre-Depends, Recommends and Suggests fields is a list of groups of alternative packages. Each group is a list of packages separated by vertical bar (or `pipe') symbols, `|'. The groups are separated by commas. Commas are to be read as `AND', and pipes as `OR', with pipes binding more tightly. Each package name is optionally followed by a version number specification in parentheses.
A version number may start with a `>>', in which case any later version will match, and may specify or omit the Debian packaging revision (separated by a hyphen). Accepted version relationships are ">>" for greater than, "<<" for less than, ">=" for greater than or equal to, "<=" for less than or equal to, and "=" for equal to.
Lists packages that this one breaks, for example by exposing bugs when the named packages rely on this one. The package maintenance software will not allow broken packages to be configured; generally the resolution is to upgrade the packages named in a Breaks field.
Lists packages that conflict with this one, for example by containing files with the same names. The package maintenance software will not allow conflicting packages to be installed at the same time. Two conflicting packages should each include a Conflicts line mentioning the other.
List of packages files from which this one replaces. This is used for allowing this package to overwrite the files of another package and is usually used with the Conflicts field to force removal of the other package, if this one also has the same files as the conflicted package.
This is a list of virtual packages that this one provides. Usually this is used in the case of several packages all providing the same service. For example, sendmail and exim can serve as a mail server, so they provide a common package (`mail-transport-agent') on which other packages can depend. This will allow sendmail or exim to serve as a valid option to satisfy the dependency. This prevents the packages that depend on a mail server from having to know the package names for all of them, and using `|' to separate the list.
The syntax of Breaks, Conflicts, Replaces and Provides is a list of package names, separated by commas (and optional whitespace). In the Breaks and Conflicts fields, the comma should be read as `OR'. An optional version can also be given with the same syntax as above for the Breaks, Conflicts and Replaces fields.
This field lists extra source packages that were used during the build of this binary package. This is an indication to the archive maintenance software that these extra source packages must be kept whilst this binary package is maintained. This field must be a list of source package names with strict (=) version relationships. Note that the archive maintenance software is likely to refuse to accept an upload which declares a Built-Using relationship which cannot be satisfied within the archive.
# Comment Package: grep Essential: yes Priority: required Section: base Maintainer: Wichert Akkerman <[email protected]> Architecture: sparc Version: 2.4-1 Pre-Depends: libc6 (>= 2.0.105) Provides: rgrep Conflicts: rgrep Description: GNU grep, egrep and fgrep. The GNU family of grep utilities may be the "fastest grep in the west". GNU grep is based on a fast lazy-state deterministic matcher (about twice as fast as stock Unix egrep) hybridized with a Boyer-Moore-Gosper search for a fixed string that eliminates impossible text from being considered by the full regexp matcher without necessarily having to look at every character. The result is typically many times faster than Unix grep or egrep. (Regular expressions containing backreferencing will run more slowly, however).