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   1 .\" dpkg manual page - deb(5)
   2 .\"
   3 .\" Copyright © 1995 Raul Miller
   4 .\" Copyright © 1996 Ian Jackson <ijackson@chiark.greenend.org.uk>
   5 .\" Copyright © 2000 Wichert Akkerman <wakkerma@debian.org>
   6 .\" Copyright © 2006-2017 Guillem Jover <guillem@debian.org>
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  20 .
  21 .TH deb 5 "%RELEASE_DATE%" "%VERSION%" "dpkg suite"
  22 .nh
  23 .SH NAME
  24 deb \- Debian binary package format
  25 .SH SYNOPSIS
  26 .IB filename .deb
  27 .SH DESCRIPTION
  28 The
  29 .B .deb
  30 format is the Debian binary package file format. It is understood
  31 since dpkg 0.93.76, and is generated by default since dpkg 1.2.0 and
  32 1.1.1elf (i386/ELF builds).
  33 .PP
  34 The format described here is used since Debian 0.93; details of the
  35 old format are described in
  36 .BR deb\-old (5).
  37 .SH FORMAT
  38 The file is an
  39 .B ar
  40 archive with a magic value of
  41 .BR !<arch> .
  42 Only the common \fBar\fP archive format is supported, with no long file
  43 name extensions, but with file names containing an optional trailing
  44 slash, which limits their length to 15 characters (from the 16 allowed).
  45 File sizes are limited to 10 ASCII decimal digits, allowing for up to
  46 approximately 9536.74 MiB member files.
  47 .PP
  48 The \fBtar\fP archives currently allowed are, the old-style (v7) format,
  49 the pre-POSIX ustar format, a subset of the GNU format (new style long
  50 pathnames and long linknames, supported since dpkg 1.4.1.17; large file
  51 metadata since dpkg 1.18.24),
  52 and the POSIX ustar format (long names supported since dpkg 1.15.0).
  53 Unrecognized tar typeflags are considered an error.
  54 Each tar entry size inside a tar archive is limited to 11 ASCII octal
  55 digits, allowing for up to 8 GiB tar entries.
  56 The GNU large file metadata support permits 95-bit tar entry sizes and
  57 negative timestamps, and 63-bit UID, GID and device numbers.
  58 .PP
  59 The first member is named
  60 .B debian\-binary
  61 and contains a series of lines, separated by newlines. Currently only
  62 one line is present, the format version number,
  63 .BR 2.0
  64 at the time this manual page was written.
  65 Programs which read new-format archives should be prepared for the
  66 minor number to be increased and new lines to be present, and should
  67 ignore these if this is the case.
  68 .PP
  69 If the major number has changed, an incompatible change has been made
  70 and the program should stop. If it has not, then the program should
  71 be able to safely continue, unless it encounters an unexpected member
  72 in the archive (except at the end), as described below.
  73 .PP
  74 The second required member is named
  75 .BR control.tar .
  76 It is a tar archive containing the package control information, either
  77 not compressed (supported since dpkg 1.17.6), or compressed with
  78 gzip (with \fB.gz\fP extension) or
  79 xz (with \fB.xz\fP extension, supported since 1.17.6),
  80 as a series of plain files, of which the file
  81 .B control
  82 is mandatory and contains the core control information, the
  83 .BR conffiles ", " triggers ", " shlibs
  84 and
  85 .B symbols
  86 files contain optional control information, and the
  87 .BR preinst ", " postinst ", " prerm
  88 and
  89 .B postrm
  90 files are optional maintainer scripts.
  91 The control tarball may optionally contain an entry for
  92 .RB ‘ . ’,
  93 the current directory.
  94 .PP
  95 The third, last required member is named
  96 .BR data.tar .
  97 It contains the filesystem as a tar archive, either
  98 not compressed (supported since dpkg 1.10.24), or compressed with
  99 gzip (with \fB.gz\fP extension),
 100 xz (with \fB.xz\fP extension, supported since dpkg 1.15.6),
 101 bzip2 (with \fB.bz2\fP extension, supported since dpkg 1.10.24) or
 102 lzma (with \fB.lzma\fP extension, supported since dpkg 1.13.25).
 103 .PP
 104 These members must occur in this exact order. Current implementations
 105 should ignore any additional members after
 106 .BR data.tar .
 107 Further members may be defined in the future, and (if possible) will be
 108 placed after these three. Any additional members that may need to be
 109 inserted after
 110 .B debian\-binary
 111 and before
 112 .B control.tar
 113 or
 114 .B data.tar
 115 and which should be safely ignored by older programs, will have names
 116 starting with an underscore,
 117 .RB ‘ _ ’.
 118 .PP
 119 Those new members which won't be able to be safely ignored will be
 120 inserted before
 121 .B data.tar
 122 with names starting with something other than underscores, or will
 123 (more likely) cause the major version number to be increased.
 124 .SH MEDIA TYPE
 125 .SS Current
 126 application/vnd.debian.binary-package
 127 .SS Deprecated
 128 application/x-debian-package
 129 .br
 130 application/x-deb
 131 .SH SEE ALSO
 132 .BR deb\-old (5),
 133 .BR dpkg\-deb (1),
 134 .BR deb\-control (5),
 135 .BR deb\-conffiles (5)
 136 .BR deb\-triggers (5),
 137 .BR deb\-shlibs (5),
 138 .BR deb\-symbols (5),
 139 .BR deb\-preinst (5),
 140 .BR deb\-postinst (5),
 141 .BR deb\-prerm (5),
 142 .BR deb\-postrm (5).