This should work: 
while (<FILE>) {
    # set modification flag to 0
    my $do_mod = 0;
    if ($do_mod) {        # if modification flag is true (>0)
        # apply substitution if matches
        s/priority/bandwidth/g;
        # if line is empty, clear modification flag
        $do_mod = 0 if (/^$/);
    } else {
        # Found first priority, mark modification flag true
        $do_mod++ if (/priority/);
    }
    print;
}

[download]
Does that make sense?
-----
"Ask not what you can do for your country. Ask what's for lunch."
-- Orson Welles

In reply to Re: Replacing duplicate string by apok
in thread Replacing duplicate string by ddrew78

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