[TriLUG] Base 64 (perl) regular expressions

[Aaron Schrab]

At 17:09 -0500 07 Mar 2012, matt at noway2.thruhere.net wrote:
>What I am not understanding, and would like to ask the perl experts 
>here is: what is the (?: part of the expression?  I don't recall 
>reading about that in any perl book and Googling is giving me some 
>pages with it used, but no explanation.

That indicates that the that set of parentheses is used for grouping, 
but the matched text shouldn't be captured for later use.  It's use 
there is likely just as a minor optimization, the expression would match 
the same things without the ?: portion.

Modifiers for parentheses including that one are documented in the 
"Extended Patterns" section of the perlre manpage.