[TriLUG] bash scripting - formatting and verifying input

Alan Porter porter at trilug.org
Thu Feb 28 21:03:05 EST 2008

 > Here's a question/challenge - how would you modify this to
 > verify that each octet is between zero and 255?

A similar question popped up in an interview (fortunately, I
was on the giving side of this one).

I usually take the stance that this SHOULD be done with a split
and an explicit check of each digit.  If that kind of function
is crammed into a regexp, then it quickly turns in to BFM (black
------- magic).

If speed is essential, and regexp is declared to be the way to
go, then the BFM should be accompanied by generous helpings of

Because in the end, (in most applications) I don't care how many
cycles my multi-GHz CPU has to spend on the problem.  I am much
more concerned with how much time my DEVELOPERS have to spend
maintaining the code after it is in place.



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