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Pack is a legacyUnix shellcompression program based onHuffman coding.^[1][2]

Theunpack utility will restore files to their original state after they have been compressed using thepack utility. If no files are specified, thestandard input will be uncompressed to the standard output.

Although obsolete, support for packed files exists in modern compression tools such asgzip^[3] and7-zip.

Files compressed bypack are typically given theextension ".z" (not to be confused with the ".Z" ofcompress). Files can be returned to their original state usingunpack. In addition, there may also be apcat command which reads in a compressed file and sends its output tostdout.

• Data compression
• Image compression
• List of Unix commands

• pack(1) in The Single UNIX Specification, Version 2, 1997, opengroup.org
• C.4 Utilities in The Open Group Base Specifications Issue 6, opengroup.org – indicates pack as excluded
• pack(1) – Version 8 Unix Programmer'sManual
• pack(1) – Solaris 11.4 User Commands ReferenceManual
• Pack command Manual

• Data compression software
• Unix archivers and compression-related utilities

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