This is not the comprehensive answer you are looking for, but, IMO, Perl has better and more exhaustive capabilities than the old unix utilities. On the other hand, grep has the -P switch which allows Perl regex syntax to be used.

In reply to Re: relationship/difference between regex in perl and other unix tools such as grep, sed, vi by toolic
in thread relationship/difference between regex in perl and other unix tools such as grep, sed, vi by Anonymous Monk

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