For the sake of simplicity, why not do the following? 
while (<DATA>) {
    print if m/bar/ && !m/foo/;
}

__DATA__
some stuff then foo then bar then more stuff
oo then bar then more stuff
some stuff then foo then bar then more stuff
some stuff then bar then more stuff

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In reply to Re: Negative Lookahead Assertion Strangness by TedPride
in thread Negative Lookahead Assertion Strangness by sas

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