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), xz (with .xz extension, supported since 1.17.6) or zstd  (with
       .zst  extension, supported since 1.19.0.5ubuntu2), as a series of plain files, of which the file control is mandatory and contains the core
       control information, the 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 1.19.0.5ubuntu2), 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-triggers(5), deb-shlibs(5), deb-symbols(5), deb-preinst(5), deb-postinst(5),
       deb-prerm(5), deb-postrm(5).

1.19.0.5                                                            2018-04-16                                                              deb(5)