Question

I have something like the following in a string:

blah blah

BEGINIGNORE
   this stuff should get stripped out
ENDIGNORE

more stuff here

I would like to do this (perl syntax): s/BEGINIGNORE.*ENDIGNORE//s — namely, strip out everything between BEGINIGNORE and ENDIGNORE, inclusive.
You would think the following would do that in Mathematica:

StringReplace[str, re["BEGINIGNORE[.\\s]*ENDIGNORE"]->""]

But it doesn’t. How do I do this in Mathematica?

PS: I define the following alias: re = RegularExpression;

Answer 1

Insert the (?s) modifier in the regex. That’s equivalent to Perl’s /s modifier and is part of standard PCRE syntax.

StringReplace[str, re["BEGINIGNORE(?s).*ENDIGNORE"]->""]

More details in this answer to a related question:
Bug in Mathematica: regular expression applied to very long string