dpkg/doc/deb-control.5

.\" Hey, Emacs!  This is an -*- nroff -*- source file.
.\" Author: Raul Miller
.\" Includes text from the debian Guidelines by Ian Jackson, Ian Murdock
.TH DEB-CONTROL 5 "January 2000" "Debian Project" "Debian GNU/Linux"
.SH NAME
deb\-control \- Debian GNU/Linux packages' master control file format
.SH SYNOPSIS
control
.SH DESCRIPTION
Each Debian package contains the master `control' file, which contains
a number of fields.  Each field begins with a tag, such as
.B Package
or
.B 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
.B Description
field, see below).
.SH REQUIRED FIELDS
.TP
.BR "Package: " "<package name>"
The value of this field determines the package name, and is used to
generate file names by most installation tools.
.TP
.BR "Version: " "<version string>"
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). If both version and revision are supplied,
they are seperated by a hyphen, `-'. For this reason, the original version
may not have a hyphen in its version number.
.TP
.BR "Maintainer: " "<fullname email>"
Should be in the format `Joe Bloggs <jbloggs@foo.com>', and is typically
the person who created the package, as opposed to the author of the
software that was packaged.
.TP
.BR "Description: " "<short description>"
.BR " " "<long description>"
.br
The format for the package description is a short brief summary on the
first line (after the "Description" field). The following lines can 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 desription must
contain a single '.' following the preceding space.
.SH OPTIONAL FIELDS
.TP
.BR "Section: " "<section>"
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.
.TP
.BR "Priority: " "<priority>"
Sets the importance of this package in relation to the system as a whole.
Common priorities are `required', `standard', `optional', `extra' etc.
.LP
In Debian, the
.B Section
and
.B Priority
fields have a defined set of accepted values based on the Policy Manual.
They are used to decide how the packages are layed out in the archive.
A list of these can be obtained from the latest version of
.B debian-policy
package.
.TP
.BR "Essential: " "<yes|no>"
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
.B Essential
package to be removed (at least not without using one of the force options).
.TP
.BR "Architecture: " "<arch|all>"
The architecture specifies which type of hardware this package was compiled
for. Common architectures are `i386', `m68k', `sparc', `alpha', `powerpc'
etc. Note that the
.B all
option is meant for packages that are architecture independent. Some examples
of this are shell or Perl scripts, or documentation.
.TP
.BR "Source: " "<source name>"
The name of the source package that this binary package came from, if
different than the name of the package itself.
.TP
.BR "Depends: " "<package list>"
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
.B Depends
field aren't installed (at least not without using the force options),
and will run the postinst scripts of packages listed in Depends: fields
before those of the packages which depend on them, and run prerm scripts
before.
.TP
.BR "Pre-Depends: " "<package list>"
List of packages that must be installed
.B 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.
.TP
.BR "Recommends: " "<package list>"
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
.B Recommends
field.
.TP
.BR Suggests: \ <package\ list>
Lists packages that are related to this one and can perhaps enhance
its usefulness, but without which installing this package is perfectly
reasonable.
.LP
The syntax of
.B Depends ,
.B Pre-Depends ,
.B Recommends
and
.B 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 item is a package name
optionally followed by a version number specification in parentheses.
.LP
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.
.TP
.BR "Conflicts: " "<package list>"
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
.B Conflicts
line mentioning the other.
.TP
.BR "Replaces: " "<package list>"
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
.B Conflicts
field to force removal of the other package, if this one also has the
same files as the conflicted package.
.TP
.BR Provides: \ <package\ list>
This is a list of virtual packages that this one provides. Usuaully this is
used in the case of several packages all providing the same service.
For example, sendmail and exim can 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 satisy 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.
.LP
The syntax of
.B Conflicts ,
.B Replaces
and
.B Provides
is a list of package names, separated by commas (and optional whitespace).
In the
.B Conflicts
field, the comma should be read as `OR'. An optional version can also be
given with the same syntax as above for the
.B Conflicts
and
.B Replaces
fields.
.SH EXAMPLE
.\" .RS
.nf
Package: grep
Essential: yes
Priority: required
Section: base
Maintainer: Wichert Akkerman <wakkerma@debian.org>
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.)
.fi
.\" .RE
.SH SEE ALSO
.BR deb (5),
.BR dpkg (8),
.BR dpkg-deb (1).