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 "29th November 1995" "Debian Project" "Debian GNU/Linux"
.SH NAME
deb\-control \- Debian GNU/Linux packages' master control file format
.SH SYNOPSIS
control
.SH DESCRIPTION
Master control file format:
.LP
The `control' file 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 is used to generate file names by some
installation tools.
.TP
.BR Version: \ <version\ string>
Typically, this is the original portable 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 '-'. For this reason,
the original version cannot have a '-' 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 packages.
.TP
.BR Description: \ <package\ description>
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 `mail', `text' and `new'.
.TP
.BR Priority: \ <priority>
Sets the importance of this package in relation to the system as a whole. Common
priorities are `base', `standard' and `optional'.
.LP
In Debian, the
.B Section
and
.B Priority
fields have a defined set of accepted values based on policy. They are used to
decide how the packages are layed out in the archive. A list of these can be
obtained from the latest
.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 will not
allow this an
.B Essential
package to be removed 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', `sparc' and `alpha'. Note that the
.B all
option is meant for packages that are architecture independent. Some examples
of this are perl scripts and documentation.
.TP
.BR Source: \ <source\ name>
The name of the source that this 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 without also installing
packages listed in its 
.B Depends
field, 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 the pre depend 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.  The package maintenance software will not moan at the
user for not selecting suggested packages, but may use the information
in the
.B Suggests
field to assist the user during package selection.
.LP
The syntax of
.B Depends ,
.B Pre-Depends ,
.B Recommends
and
.B Suggests
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.  Each package is a package name
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).  Commas are to be read as `AND', and pipes as
`OR', with pipes binding more tightly.
.LP
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 (an example would be Smail vs. Sendmail).
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 that 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 smail both can serve as a mail server, so they provide a common package
on which other packages can depend. This will allow sendmail or smail to serve
as a valid option to satisy the one 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 seperate 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
.PP
.RS
.nf
Package: grep
Essential: yes
Priority: required
Section: base
Maintainer: Wichert Akkerman <wakkerma@debian.org>
Architecture: sparc
Version: 2.3-7
Pre-Depends: libc6 (>= 2.0.105)
Description: GNU grep, egrep and fgrep.
 The GNU set of grep tools. Many times faster than standard
 unix grep.
.fi
.RE
.PP
.SH SEE ALSO
.BR deb (5),
.BR dpkg (8),
.BR dpkg-deb (1),
.BR dselect (8).