Use a negative look-ahead assertion, see perlre for information about that.

$pattern = '(?!.*foo)';

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It is, however, very expensive. If changing the code is possible, do so. 

2;0 juerd@ouranos:~$ perl -e'undef christmas'
Segmentation fault
2;139 juerd@ouranos:~$

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In reply to Re: regex problem by Juerd
in thread regex problem by Anonymous Monk

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