If you are trying to pass file handles to a subroutine, then

open ( FILE_ONE, "foo.txt" ) || die "Unable to open foo: $!";
open ( FILE_TWO, "bar.txt" ) || die "Unable to open bar: $!";

CompareFiles ( \*FILE_ONE, \*FILE_TWO );

close ( FILE_TWO );
close ( FILE_ONE );
[download]

will work fine. Once the file handle has reached the subroutine you can select it and read from it.

Update: Removed reference to Algorithm::Diff; I mis-read the question to be referring to find 'differences' between two files.

--t. alex

"There was supposed to be an earth-shattering kaboom!" --Marvin the Martian