The CPAN autobundle can be used to ease perl upgrades, by creating a special bundle containing all the installed modules of the current version of perl. This bundle can then be installed once the new version of perl is installed.

cpan> autobundle


Wrote bundle file
/var/spool/cpan/Bundle/Snapshot_2004_10_01_00.pm


cpan> quit

# upgrade perl here …

# cpan
cpan> install Bundle::Snapshot_2004_10_01_00