As others mentioned, you need to use either 'not' or '()' - since '!' has a higher order of precedence than '=~'. From perlop: 
Operator Precedence and Associativity
...

           right       ! ~ \ and unary + and -
           left        =~ !~
           ...
           right       not

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-- zigdon

In reply to Re: regular expressions with ! by zigdon
in thread regular expressions with ! by egunnar

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