Pack is a legacy
Unix shell
A Unix shell is a Command-line_interface#Command-line_interpreter, command-line interpreter or shell (computing), shell that provides a command line user interface for Unix-like operating systems. The shell is both an interactive command languag ...
compression program based on
Huffman coding
In computer science and information theory, a Huffman code is a particular type of optimal prefix code that is commonly used for lossless data compression. The process of finding or using such a code is Huffman coding, an algorithm developed by ...
.
The unpack utility will restore files to their original state after they have been compressed using the ''pack'' utility. If no files are specified, the
standard input will be uncompressed to the standard output.
Although obsolete, support for packed files exists in modern compression tools such as
gzip and
7-zip.
Description of program
Files compressed by ''pack'' are typically given the
extension ".z" (not to be confused with the ".Z" of
compress). Files can be returned to their original state using ''unpack''. In addition, there may also be a ''pcat'' command which reads in a compressed file and sends its output to
stdout.
See also
*
Data compression
In information theory, data compression, source coding, or bit-rate reduction is the process of encoding information using fewer bits than the original representation. Any particular compression is either lossy or lossless. Lossless compressi ...
*
Image compression
*
List of Unix commands
References
External links
pack(1)in The Single UNIX Specification, Version 2, 1997, opengroup.org
in The Open Group Base Specifications Issue 6, opengroup.org – indicates pack as excluded
*
*
Pack command Manual
{{Compression Software Implementations
Data compression software
Unix archivers and compression-related utilities