it-ebooks watermark

#!/usr/bin/env perl

    $file = $ARGV[0] or exit;

    open $fh, '<', $file or die "$!";
    binmode $fh;
    $content = do { local $/; <$fh> };

    $content=~s#www.it-ebooks.info##sg;
    $content=~s#/Type /Annot[^>]*?\(http:///\).>>##sg;

    open $fh, '>', $file or die "$!";
    binmode $fh;
    print $fh $content;