Apache Reference: mod_alias

mod_alias - Simple URL Translation and Redirection
Since Apache 1.0, src/modules/standard/mod_alias.c
Rob McCool, David Robinson, Robert S. Thau (1995)

mod_alias is the father of all URL manipulation modules. It has existed since the early Apache days and provides a limited, but easy-to-understand mechanism for mapping URLs to file names. The original idea was that one could translate URLs to file names by mapping URL prefixes to directory paths on the file system. The AliasMatch and RedirectMatch directives use regular expressions instead of prefixes to achieve more flexibility.

Directives:

Alias    AliasMatch
Redirect    RedirectMatch
RedirectPermanent    RedirectTemp
ScriptAlias    ScriptAliasMatch