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deb-version(7) dpkg suite deb-version(7)
deb-version - Debian package version number format
[epoch:]upstream-version[-debian-revision]
Version numbers as used for Debian binary and source packages
consist of three components. These are:
epoch
This is a single (generally small) unsigned integer. It may
be omitted, in which case zero is assumed. If it is omitted
then the upstream-version may not contain any colons.
It is provided to allow mistakes in the version numbers of
older versions of a package, and also a package's previous
version numbering schemes, to be left behind.
upstream-version
This is the main part of the version number. It is usually
the version number of the original (“upstream”) package from
which the .deb file has been made, if this is applicable.
Usually this will be in the same format as that specified by
the upstream author(s); however, it may need to be
reformatted to fit into the package management system's
format and comparison scheme.
The comparison behavior of the package management system with
respect to the upstream-version is described below. The
upstream-version portion of the version number is mandatory.
The upstream-version may contain only alphanumerics
(“A-Za-z0-9”) and the characters . + - : ~ (full stop, plus,
hyphen, colon, tilde) and should start with a digit. If
there is no debian-revision then hyphens are not allowed; if
there is no epoch then colons are not allowed.
debian-revision
This part of the version number specifies the version of the
Debian package based on the upstream version. It may contain
only alphanumerics and the characters + . ~ (plus, full stop,
tilde) and is compared in the same way as the upstream-
version is.
It is optional; if it isn't present then the upstream-version
may not contain a hyphen. This format represents the case
where a piece of software was written specifically to be
turned into a Debian package, and so there is only one
“debianization” of it and therefore no revision indication is
required.
It is conventional to restart the debian-revision at ‘1’ each
time the upstream-version is increased.
Dpkg will break the version number apart at the last hyphen
in the string (if there is one) to determine the upstream-
version and debian-revision. The absence of a debian-
revision compares earlier than the presence of one (but note
that the debian-revision is the least significant part of the
version number).
Sorting algorithm
The upstream-version and debian-revision parts are compared by
the package management system using the same algorithm:
The strings are compared from left to right.
First the initial part of each string consisting entirely of non-
digit characters is determined. These two parts (one of which
may be empty) are compared lexically. If a difference is found
it is returned. The lexical comparison is a comparison of ASCII
values modified so that all the letters sort earlier than all the
non-letters and so that a tilde sorts before anything, even the
end of a part. For example, the following parts are in sorted
order: ‘~~’, ‘~~a’, ‘~’, the empty part, ‘a’.
Then the initial part of the remainder of each string which
consists entirely of digit characters is determined. The
numerical values of these two parts are compared, and any
difference found is returned as the result of the comparison.
For these purposes an empty string (which can only occur at the
end of one or both version strings being compared) counts as
zero.
These two steps (comparing and removing initial non-digit strings
and initial digit strings) are repeated until a difference is
found or both strings are exhausted.
Note that the purpose of epochs is to allow us to leave behind
mistakes in version numbering, and to cope with situations where
the version numbering scheme changes. It is not intended to cope
with version numbers containing strings of letters which the
package management system cannot interpret (such as ‘ALPHA’ or
‘pre-’), or with silly orderings.
The tilde character and its special sorting properties were
introduced in dpkg 1.10 and some parts of the dpkg build scripts
only gained support for it later in the 1.10.x series.
deb-control(5), deb(5), dpkg(1)
This page is part of the dpkg (Debian Package Manager) project.
Information about the project can be found at
⟨https://wiki.debian.org/Teams/Dpkg/⟩. If you have a bug report
for this manual page, see
⟨http://bugs.debian.org/cgi-bin/pkgreport.cgi?src=dpkg⟩. This
page was obtained from the project's upstream Git repository ⟨git
clone https://git.dpkg.org/git/dpkg/dpkg.git⟩ on 2024-06-14. (At
that time, the date of the most recent commit that was found in
the repository was 2024-05-21.) If you discover any rendering
problems in this HTML version of the page, or you believe there
is a better or more up-to-date source for the page, or you have
corrections or improvements to the information in this COLOPHON
(which is not part of the original manual page), send a mail to
[email protected]
1.22.6-77-g86fe7 2024-03-10 deb-version(7)
Pages that refer to this page: deb-buildinfo(5), deb-changelog(5), deb-changes(5), deb-control(5), deb-src-control(5), dsc(5)
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HTML rendering created 2024-06-26 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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