View source for Pack (Unix)

{{FormatInfo
|name=pack (Unix)
|formattype=electronic
|subcat=Compression
|extensions={{ext|z}}
|wikidata={{wikidata|Q29650301}}
}}
{{DISPLAYTITLE:pack (Unix)}}'''pack''' is a command in Unix-style operating systems to compress files using [[Huffman coding]]. Files normally have a lowercase '''.z''' extension, appended to their names including any other extension they may already have in their uncompressed versions, e.g., '''file.txt.z'''.

== See also ==
* [[compress (Unix)]]
* [[compact (Unix)]]

== Identification ==
Files begin with bytes {{magic|0x1F 0x1E}}.

The gzip source code mentions an "old pack format" that begins with {{magic|0x1F 0x1F}}.

See also [[compress (Unix)#The 0x1f compression family]].

== Software ==
* [https://www.gnu.org/software/gzip/ GNU gzip] ''[Note: Broken in v1.6 - 1.8]''
* [https://github.com/temisu/ancient Ancient]
* {{Deark}}
* [https://www.tuhs.org/cgi-bin/utree.pl?file=V10 Tenth Edition of Unix] → v10src.tar.bz2 → cmd/pack/ - Source code
* illumos: [http://src.illumos.org/source/xref/illumos-gate/usr/src/cmd/pack/ pack], [http://src.illumos.org/source/xref/illumos-gate/usr/src/cmd/unpack/ unpack] - Source code
* https://github.com/koalaman/pack - A modern implementation in Haskell (write-only)

== Sample files ==
* https://telparia.com/fileFormatSamples/archive/pack/

== References ==
* [http://www.mkssoftware.com/docs/man1/pack.1.asp pack man page (MKS Toolkit)]
* [http://publib.boulder.ibm.com/infocenter/zos/v1r13/index.jsp?topic=%2Fcom.ibm.zos.r13.bpxa500%2Fpack.htm pack man page (IBM)]
* [https://www.vidarholen.net/contents/blog/?p=691 An ode to pack: gzip’s forgotten decompressor]