compress (Unix)

From Just Solve the File Format Problem
Jump to: navigation, search
File Format
Name compress (Unix)
Ontology
Extension(s) .Z
MIME Type(s) application/x-compress
Wikidata ID Q29209269
Released ~1984
This article is about a specific file format. For compression in general, see Compression.

compress is a Unix command line utility, and a general-purpose compressed file format. Its compression algorithm is based on LZW.

Contents

Identifiers

The conventional filename extension is a capitalized .Z.

Identification

Files begin with bytes 1f 9d.

See also

Formats that could be considered to be the successors of compress include Freeze/Melt, and (especially) Gzip.

The 0x1f compression family

There are several compressed file formats, with similar features, that begin with byte value 0x1f (octal 037; decimal 31). We arbitrarily choose compress as the representative example, and list the formats here.

Signature (hex) Format
1f 1e pack (Unix)
1f 1f pack (Unix) - old format
1f 8b gzip
1f 9d compress
1f 9e Freeze/Melt - old format
1f 9f Freeze/Melt - new format
1f a0 SCO compress LZH
1f a1 Quasijarus Strong Compression
1f ff or ff 1f compact (Unix)

Software

Sample files

External links

Personal tools
Namespaces

Variants
Actions
Navigation
Toolbox