[bct]

> Gentoo tries to handle this by managing all config files in CVS, so you can diff different versions and merge them.

Am I missing something? I wish it did this, but unless something has changed recently it just gives you a tool for merging updates in (and doesn't store old revisions).

[Elfan]

dispatch-conf and etc-update are the two config updating tools included with gentoo's portage. dispatch-conf is the newer and preferred tool.

Be default dispatch-conf keeps a backup of your config files in /etc/config-archive. Optionally it can use rcs to track changes.

[papersmith]

Oops, I keep forgeting this is not part of portage. This is done so often that it should really be made a sensible default for any mainstream distribution.