This is File::Sort 1.00, for sorting files similarly to sort(1).  Written
primarily for MacPerl users who do not have sort(1) and because of memory
limitations cannot sort files in memory, but works on all perls, and can
be useful for portable sorting of large files, or for any system that
doesn't have a sort(1) and is virtual-memory-deprived (including Windows).

WWW: https://metacpan.org/release/File-Sort