Archiving and Compression

Overview

• UNIX mantra: every tool should do one thing well

• ⟶ Compression is one thing, archiving is a different thing

• Archive tools

  • tar - most popular (but “ugly as hell”, Quote from Al Viro)

  • cpio - older but cleaner - Archivformat von Linux’s initramfs

• Compression tools. Good as filters in a pipeline.

  • gzip, common extension .gz

  • bzip2, common extension .bz2

  • lzma, common extension .lzma

Compression Tools: Comparison

Compressing a .tar file of the Linux kernel tree (roughly 430MB):

Tool	Time consumed	Size
gzip	20s	95MB
bzip2	1m 11s	74MB
lzma	5m 32s	64MB

Note

The numbers have been taken ages ago, so they should be seen only in relation