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Re: Allow only letters and numbers?

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From:
merlyn
Date:
February 21, 2002 19:50
Subject:
Re: Allow only letters and numbers?
Message ID:
m1664q18g1.fsf@halfdome.holdit.com
>>>>> "Timothy" == Timothy Johnson <tjohnson@sandisk.com> writes:

Timothy> If you don't mind having underscores in your text, you could also do this:

Timothy> if($string !~ /^\w+$/){  #If the string does not have only letters, digits,
Timothy> and underscores from start to finish (\w)

Nope, that also permits "fred\n".  Remember that $ is the same as /\n?\z/.
You want \z instead.

Very common mistake, and could have drastic effects on security.
Bad.

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