Compress (Unix)
From Just Solve the File Format Problem
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Formats that could be considered to be the successors of ''compress'' include [[Freeze/Melt]], and (especially) [[Gzip]]. | 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 {{magic|0x1f}} (octal 037; decimal 31). We arbitrarily choose ''compress'' as the representative example, and list the formats here. | ||
| + | |||
| + | {| class="wikitable" | ||
| + | ! Signature (hex) !! Format | ||
| + | |- | ||
| + | | <code>1f 1e</code> || [[pack (Unix)]] | ||
| + | |- | ||
| + | | <code>1f 1f</code> || [[pack (Unix)]] - old format | ||
| + | |- | ||
| + | | <code>1f 8b</code> || [[gzip]] | ||
| + | |- | ||
| + | | <code>1f 9d</code> || compress | ||
| + | |- | ||
| + | | <code>1f 9e</code> || [[Freeze/Melt]] - old format | ||
| + | |- | ||
| + | | <code>1f 9f</code> || [[Freeze/Melt]] - new format | ||
| + | |- | ||
| + | | <code>1f a0</code> || [[SCO compress LZH]] | ||
| + | |- | ||
| + | | <code>1f a1</code> || [[Quasijarus Strong Compression]] | ||
| + | |- | ||
| + | | <code>1f ff</code> or <code>ff 1f</code> || [[compact (Unix)]] | ||
| + | |} | ||
== Software == | == Software == | ||
Revision as of 14:40, 18 September 2020
- 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
- SCO compress LZH - variant
- Quasijarus Strong Compression - variant
- pack (Unix) - predecessor
- compact (Unix) - predecessor
- Squash (RISC OS)
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) |
