# deb

## 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), zstd (with **.zst** extension, supported since dpkg 1.21.18),
           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), zstd (with
           **.zst** extension, supported since dpkg 1.21.18), 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
    


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