Just to re-iterate the chatterbox conversation:

If you're looking for speed and efficiency, then Perl is probably not going to figure in the solution.

The data looks fairly compatible with the Solaris sort command. If it chokes on the volume of data, try the GNU sort.

If you still have problems, try using:

• The 'split' command to subdivide the main file into temp files
• The 'sort' command to sort each temp file (perhaps in parallel, but probably not due to memory demands)
• The 'sort -m' command to merge the sorted temp files
• The 'rm' command to clean up the temp files :-)