in reply to compare two files

If you're trying to alter file1 to be the set complement of the two files, you could use this to do it on the fly and not create a temp file: 
use Tie::File;

my %seen;
tie my @file1, 'Tie::File', 'file1' or die;
tie my @file2, 'Tie::File', 'file2' or die;

foreach (@file2) { chomp; $seen{$_}++; }
@file1 = grep { chomp; !$seen{$_} } @file1;

untie(@file1);
untie(@file2);

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Re^2: compare two files
by citromatik (Curate) on Jul 24, 2007 at 15:27 UTC

    Once you have both files as lists, you can use List::MoreUtils to test uniq-ness:

    use Tie::File;
use List::MoreUtils qw(uniq);

tie my @file1, 'Tie::File', 'file1' or die;
tie my @file2, 'Tie::File', 'file2' or die;

print join "\n",uniq (@file1,@file2);

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    citromatik

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