Idiot's guide to regular expressions?

[Graham Samuel]

The RunRev docs yield the explanation and definition of regular  
expressions, used for example in the matchText function, to the  
following link:

<http://www.pcre.org/man.txt>


while doubtless definitive, this amounts to an academic thesis of many  
many pages, and of little practical use to folks not brought up on  
Unix, such as myself, who don't have quite a few hours to spare.

Of course there is no shortage of other texts on regex to be found on  
Google, but can anyone suggest a concise primer that will help me  
parse ascii strings without too many tears? If there is one, maybe  
it's time to suggest that RunRev mention it in the documentation.

TIA

Graham