ucf

Description

Update Configuration File(s): preserve user changes to config files
Debian policy mandates that user changes to configuration files must be
preserved during package upgrades. The easy way to achieve this behavior
is to make the configuration file a 'conffile', in which case dpkg
handles the file specially during upgrades, prompting the user as
needed.

This is appropriate only if it is possible to distribute a default
version that will work for most installations, although some system
administrators may choose to modify it. This implies that the
default version will be part of the package distribution, and must
not be modified by the maintainer scripts during installation (or at
any other time).

This script attempts to provide conffile-like handling for files that
may not be labelled conffiles, and are not shipped in a Debian package,
but handled by the postinst instead. This script allows one to
maintain files in /etc, preserving user changes and in general
offering the same facilities while upgrading that dpkg normally
provides for 'conffiles'.

Additionally, this script provides facilities for transitioning a
file that had not been provided with conffile-like protection to come
under this schema, and attempts to minimize questions asked at
installation time. Indeed, the transitioning facility is better than the
one offered by dpkg while transitioning a file from a non-conffile to
conffile status.