dpkg-split

dpkg-split - Debian package archive split/join tool

dpkg-split -s|--split complete-archive [prefix]
dpkg-split -j|--join part part ...
dpkg-split -I|--info part part ...
dpkg-split -a|--auto -o complete-output part
dpkg-split -l|--listq
dpkg-split -d|--discard [package package ...]

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.

--split, -s

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.

--join, -j

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.deb.

--info, -I

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).

--auto, -a

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.)

--listq, -l

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.

--discard, -d

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, -h

Prints dpkg-split’s usage message, giving a summary of its options and their uses.

--version

Prints dpkg-split’s version number.

--licence

Prints information about dpkg-split’s copyright licensing and lack of warranty. (The American spelling --license is also supported.)

--depotdir directory

Specifies an alternative directory for the queue of parts awaiting automatic reassembly. The default is /var/lib/dpkg.

--partsize|-S kbytes

Specifies the maximum part size when splitting, in kilobytes (1024 bytes). The default is 450Kb.

--output|-O 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).

--npquiet, -Q

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.

An exit status of 0 indicates that the requested split, merge, or other command succeeded. --info commands count as successful even if the files are not binary package parts.

An exit status of 1 occurs only with --auto and indicates that the part file was not a binary package part.

An exit status of 2 indicates some kind of trouble, such as a system call failure, a file that looked like a package part file but was corrupted, a usage error or some other problem.

dpkg-split uses some rather out-of-date conventions for the the filenames of Debian packages.

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.

The architecture is not represented in the part files’ header, only in the control information of the contained binary package file, and it is not present in the filenames generated.

/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.

deb(5), deb-control(5), dpkg-deb(1), dpkg(8)

dpkg-split and this manpage were written by Ian Jackson. They are Copyright (C) 1995-1996 by him and released under the GNU General Public Licence; there is NO WARRANTY. See /usr/share/dpkg/copyright and /usr/share/common-licenses/GPL for details.