Since the beginning of its existence, Perl has been specifically tuned to work with large files .. but it's still possible to be inefficient when dealing with large files, you have shown. ;)

The questions you need to ask yourself are,

• Do you need to have the entire 1.6G file in memory, or do you only need some of the records?
• If you need all of the records, can you pick out the parts of the line that you're interested as the lines go by?

If you can give us a better idea of what process you're going through, we can probably give you a better idea how to use Perl effectively and efficiently.