deb - Debian binary package format
filename.deb
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).
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.
application/vnd.debian.binary-package
application/x-debian-package
application/x-deb
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).