my %regexen = (
    '*' => [
        { 'replace' => qr/blah/,  'with' => 'duh' },
        { 'replace' => qr/baz/,   'with' => 'quuz' },
        { 'replace' => qr/(b)ar/, 'with' => '$1um' }
    ],
    'cgi-bin' => [
        {
            'replace' => qr!usr/local/bin/perl!,
            'with'    => 'usr/bin/perl'
        }
    ]
);

foreach my $directory ( '*', 'cgi-bin' ) {
    foreach my $file ( glob("$directory/*") ) {
        next
          if (
            $file =~ m/\.(jpg|png|gif|zip|gz|jar|pl|bak|\~)$/i );
        print "Processing... $file (old file as ${file}.bak\n";
        open( INF, $file )
          or die("Can't open $file for input: $!\n");
        open( OUTF, '>' . $file . '.new' )
          or die("Can't open $file.new for output: $!\n");
        binmode(INF);
        binmode(OUTF);
        while ( my $line = <INF> ) {
            foreach my $rx ( @{ $regexen{$directory} } ) {
                $line =~ s/$rx->{'replace'}/$rx->{'with'}/;
            }
            print OUTF $line;
        }
        close(INF);
        close(OUTF);
        rename( $file, $file . '.bak' );
        rename( $file . '.new', $file );
    }
}