negating a word

Using grep, I want to do something like this:

(hello).*foobar

...which means, find all lines that have "foobar"
as long as it is not
preceded somewhere with the word "hello."  I can't
get that to work.
What am I doing wrong?


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#!/usr/bin/perl -w
use strict;
open FILE, "name of the file";
while(<FILE>){ print $_ if /(?<!hello)foobar/};
close FILE;

Do it with perl


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