NixOS/nixos — pull request #21 by peti (2012-07-26 22:41:22+00:00)
Title: Assign fixed a UID and GID for the user dedicated to running Apache

This change is somewhat intrusive for all sites that had Apache installed prior
to this patch, because these systems have such an user/group already, but with
different numeric values: the change of those numeric values breaks ownership
of some files. To migrate your system, edit the file "/etc/groups" and replace
the old GID value with 54. (NixOS can't do that for you because it refuses to
change a GID that identifies the primary group of a user.) Then run

find / -xdev -uid $oldUID -exec chown 54 {} +
find / -xdev -gid $oldGID -exec chgrp 54 {} +

to update ownership of all files that are supposed to be owned by Apache.