NAME | SYNOPSIS | DESCRIPTION | NOTES | SEE ALSO | COLOPHON

deb-version(5)                   dpkg suite                   deb-version(5)

NAME         top

       deb-version - Debian package version number format

SYNOPSIS         top

       [epoch:]upstream-version[-debian-revision]

DESCRIPTION         top

       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
              “debianisation” 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.

NOTES         top

       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.

SEE ALSO         top

       deb-control(5), deb(5), dpkg(1)

COLOPHON         top

       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://git.debian.org/git/dpkg/dpkg.git⟩ on 2017-05-03.  If you dis‐
       cover 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 man-pages@man7.org

1.18.15-3-ga2ef                  1970-01-01                   deb-version(5)

Pages that refer to this page: deb-buildinfo(5)deb-changelog(5)deb-changes(5)deb-control(5)deb-src-control(5)dsc(5)