Or somewhat more efficiently, 

print "Doesn't contain 'system'" 
    if $string =~ m[^(?!.*system)];

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Examine what is said, not who speaks.
"Efficiency is intelligent laziness." -David Dunham
"When I'm working on a problem, I never think about beauty. I think only how to solve the problem. But when I have finished, if the solution is not beautiful, I know it is wrong." -Richard Buckminster Fuller
If I understand your problem, I can solve it! Of course, the same can be said for you.

In reply to Re: Backtracking problem with .*(?!bar) by BrowserUk
in thread Backtracking problem with .*(?!bar) by olivierp

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