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deb(5)                                       dpkg suite                                       deb(5)



NAME
       deb - Debian binary package format

SYNOPSIS
       filename.deb

DESCRIPTION
       The .deb format is the Debian binary package file format. It is understood since dpkg
       0.93.76, and is generated by default since dpkg 1.2.0 and 1.1.1elf (i386/ELF builds).

       The format described here is used since Debian 0.93; details of the old format are described
       in deb-old(5).

FORMAT
       The file is an ar archive with a magic value of !<arch>.  Only the common ar archive format
       is supported, with no long file name extensions, but with file names containing an optional
       trailing slash, which limits their length to 15 characters (from the 16 allowed).  File sizes
       are limited to 10 ASCII decimal digits, allowing for up to approximately 9536.74 MiB member
       files.

       The tar archives currently allowed are, the old-style (v7) format, the pre-POSIX ustar
       format, a subset of the GNU format (new style long pathnames and long linknames, supported
       since dpkg 1.4.1.17; large file metadata since dpkg 1.18.24), and the POSIX ustar format
       (long names supported since dpkg 1.15.0).  Unrecognized tar typeflags are considered an
       error.  Each tar entry size inside a tar archive is limited to 11 ASCII octal digits,
       allowing for up to 8 GiB tar entries.  The GNU large file metadata support permits 95-bit tar
       entry sizes and negative timestamps, and 63-bit UID, GID and device numbers.

       The first member is named debian-binary and contains a series of lines, separated by
       newlines. Currently only one line is present, the format version number, 2.0 at the time this
       manual page was written.  Programs which read new-format archives should be prepared for the
       minor number to be increased and new lines to be present, and should ignore these if this is
       the case.

       If the major number has changed, an incompatible change has been made and the program should
       stop. If it has not, then the program should be able to safely continue, unless it encounters
       an unexpected member in the archive (except at the end), as described below.

       The second required member is named control.tar.  It is a tar archive containing the package
       control information, either not compressed (supported since dpkg 1.17.6), or compressed with
       gzip (with .gz extension) or xz (with .xz extension, supported since 1.17.6), as a series of
       plain files, of which the file control is mandatory and contains the core control
       information, the md5sums, conffiles, triggers, shlibs and symbols files contain optional
       control information, and the preinst, postinst, prerm and postrm files are optional
       maintainer scripts.  The control tarball may optionally contain an entry for ‘.’, the current
       directory.

       The third, last required member is named data.tar.  It contains the filesystem as a tar
       archive, either not compressed (supported since dpkg 1.10.24), or compressed with gzip (with
       .gz extension), xz (with .xz extension, supported since dpkg 1.15.6), bzip2 (with .bz2
       extension, supported since dpkg 1.10.24) or lzma (with .lzma extension, supported since dpkg
       1.13.25).

       These members must occur in this exact order. Current implementations should ignore any
       additional members after data.tar.  Further members may be defined in the future, and (if
       possible) will be placed after these three. Any additional members that may need to be
       inserted after debian-binary and before control.tar or data.tar and which should be safely
       ignored by older programs, will have names starting with an underscore, ‘_’.

       Those new members which won't be able to be safely ignored will be inserted before data.tar
       with names starting with something other than underscores, or will (more likely) cause the
       major version number to be increased.

MEDIA TYPE
   Current
       application/vnd.debian.binary-package

   Deprecated
       application/x-debian-package

       application/x-deb

SEE ALSO
       deb-old(5), dpkg-deb(1), deb-control(5), deb-conffiles(5), deb-md5sums(5), deb-triggers(5),
       deb-shlibs(5), deb-symbols(5), deb-preinst(5), deb-postinst(5), deb-prerm(5), deb-postrm(5).



1.21.1                                       2025-09-09                                       deb(5)