While you might find a solution by just sticking to regexes for the problem shown, it's typically less painful to handle the parse states in perl code. Not the world's sexiest code, but works: 
my $text = "This is a test for the word blue more things blue and then
+ some very large text with a lot of things blue and done";

my $words_to_go = 0;
my @keeper      = ();

while($text =~ /(\w+)/g) {
    if($1 eq "blue") {
        if(! $words_to_go) {
            print "$_ " for @keeper;
        }
        print "$1 ";
        $words_to_go = 5;
    } elsif($words_to_go) {
        $words_to_go--;
        print "$1 ";
    } else {
        push @keeper, $1;
        shift @keeper if @keeper > 5;
    }
}

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In reply to Re: regexp matching around a word by saintmike
in thread regexp matching around a word by kidd

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