dpkg-split(1) dpkg suite dpkg-split(1)
NAME
dpkg-split - Debian package archive split/join tool
SYNOPSIS
dpkg-split [option...] command
DESCRIPTION
dpkg-split splits Debian binary package files into smaller parts and
reassembles them again, to support the storage of large package files
on small media such as floppy disks.
It can be operated manually using the --split, --join and --info
options.
It also has an automatic mode, invoked using the --auto option, where
it maintains a queue of parts seen but not yet reassembled and
reassembles a package file when it has seen all of its parts. The
--listq and --discard options allow the management of the queue.
All splitting, joining and queueing operations produce informative
messages on standard output; these may safely be ignored.
COMMANDS
-s, --split complete-archive [prefix]
Splits a single Debian binary package into several parts.
The parts are named prefix.NofM.deb where N is the part number,
starting at 1, and M is the total number of parts (both in
decimal).
If no prefix is supplied then the complete-archive filename is
taken, including directory, with any trailing .deb removed.
-j, --join part...
Joins the parts of a package file together, reassembling the
original file as it was before it was split.
The part files given as arguments must be all the parts of exactly
the same original binary file. Each part must occur exactly once
in the argument list, though the parts to not need to be listed in
order.
The parts must of course all have been generated with the same part
size specified at split time, which means that they must usually
have been generated by the same invocation of dpkg-split --split.
The parts' filenames are not significant for the reassembly
process.
By default the output file is called package_version_arch.deb.
-I, --info part...
Prints information, in a human-readable format, about the part
file(s) specified. Arguments which are not binary package parts
produce a message saying so instead (but still on standard output).
-a, --auto -o complete-output part
Automatically queue parts and reassemble a package if possible.
The part specified is examined, and compared with other parts of
the same package (if any) in the queue of packages file parts.
If all parts of the package file of which part is a part are
available then the package is reassembled and written to complete-
output (which should not usually already exist, though this is not
an error).
If not then the part is copied into the queue and complete-output
is not created.
If part is not a split binary package part then dpkg-split will
exit with status 1; if some other trouble occurs then it will exit
with status 2.
The --output or -o option must be supplied when using --auto. (If
this were not mandatory the calling program would not know what
output file to expect.)
-l, --listq
Lists the contents of the queue of packages to be reassembled.
For each package file of which parts are in the queue the output
gives the name of the package, the parts in the queue, and the
total number of bytes stored in the queue.
-d, --discard [package...]
This discards parts from the queue of those waiting for the
remaining parts of their packages.
If no package is specified then the queue is cleared completely; if
any are specified then only parts of the relevant package(s) are
deleted.
-?, --help
Show the usage message and exit.
--version
Show the version and exit.
OPTIONS
--depotdir directory
Specifies an alternative directory for the queue of parts awaiting
automatic reassembly. The default is /var/lib/dpkg/parts.
--admindir directory
Set the administrative directory to directory (since dpkg 1.21.10).
This is where the statoverride file is stored. Defaults to
«/var/lib/dpkg» if DPKG_ADMINDIR has not been set.
--root directory
Set the root directory to directory (since dpkg 1.21.10), which
sets the installation directory to «directory» and the
administrative directory to «directory/var/lib/dpkg» if DPKG_ROOT
has not been set.
-S, --partsize kibibytes
Specifies the maximum part size when splitting, in kibibytes (1024
bytes). The default is 450 KiB.
-o, --output complete-output
Specifies the output file name for a reassembly.
This overrides the default for a manual reassembly (--join) and is
mandatory for an automatic queue-or-reassemble (--auto).
-Q, --npquiet
When doing automatic queue-or-reassembly dpkg-split usually prints
a message if it is given a part that is not a binary package part.
This option suppresses this message, to allow programs such as dpkg
to cope with both split and unsplit packages without producing
spurious messages.
--msdos
Forces the output filenames generated by --split to be MSDOS-
compatible.
This mangles the prefix - either the default derived from the input
filename or the one supplied as an argument: alphanumerics are
lowercased, plus signs are replaced by x's and all other characters
are discarded.
The result is then truncated as much as is necessary, and filenames
of the form prefixNofM.deb are generated.
EXIT STATUS
0 The requested split, merge, or other command succeeded. --info
commands count as successful even if the files are not binary
package parts.
1 Only occurs with --auto and indicates that the part file was not a
binary package part.
2 Fatal or unrecoverable error due to invalid command-line usage, a
file that looked like a package part file but was corrupted, or
interactions with the system, such as accesses to the database,
memory allocations, etc.
ENVIRONMENT
DPKG_ROOT
If set and --root option has not been specified, it will be used as
the filesystem root directory (since dpkg 1.21.10).
DPKG_ADMINDIR
If set and the --admindir or --root options have not been
specified, it will be used as the dpkg data directory (since dpkg
1.21.10).
DPKG_DEBUG
Sets the debug mask (since dpkg 1.21.10) from an octal value. The
currently accepted flags are described in the dpkg --debug option,
but not all these flags might have an effect on this program.
DPKG_COLORS
Sets the color mode (since dpkg 1.18.5). The currently accepted
values are: auto (default), always and never.
SOURCE_DATE_EPOCH
If set, it will be used as the timestamp (as seconds since the
epoch) in the deb-split(5)'s ar(5) container.
Since dpkg 1.18.11.
FILES
/var/lib/dpkg/parts
The default queue directory for part files awaiting automatic
reassembly.
The filenames used in this directory are in a format internal to
dpkg-split and are unlikely to be useful to other programs, and in
any case the filename format should not be relied upon.
SECURITY
Examining or joining untrusted split package archives should be
considered a security boundary, and any breakage of that boundary
stemming from these operations should be considered a security
vulnerability. Performing these operations over untrusted data as root
is strongly discouraged.
Auto-accumulating and discarding split package parts are considered
privileged operations that might allow root escalation. These
operations must never be delegated to an untrusted user or be done on
untrusted packages, as that might allow root access to the system.
Splitting package archives should only be performed over trusted data.
BUGS
Full details of the packages in the queue are impossible to get without
digging into the queue directory yourself.
There is no easy way to test whether a file that may be a binary
package part is one.
SEE ALSO
deb(5), deb-control(5), dpkg-deb(1), dpkg(1).
1.22.6 2025-09-18 dpkg-split(1)
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