O.K. Monks, I wrote a script that uses Find::File to recursively parse a directory and change parts of the files it finds using a reg/ex. I got some strange (at least to me) results from one particular substitution:

The guts of this substitution look like this: 

$matchtext = "http://www.foo.bar/somepage.pl?";
$substitutetext = "http://www.new.site/somenewpage?";
s/$matchtext/$substitutetext/;

[download]

This code was giving me this result:
http://www.foo.bar/somepage.pl? was becoming
http://www.new.site/somenewpage.pl?? #note: 2 "?"'s

Oh yeah, I thought, i forgot about the "?" modifier for reg/ex. So I reran my script with this... 

$matchtext = "http://www.new.site/somenewpage.pl\?\?";
$substitutetext = "http://www.new.site/somenewpage.pl\?";
s/$matchtext/$substitutetext/;

[download]

...thinking that I would simply escape out the "?" character.

After running this script, the orignal string:
http://www.new.site/somenewpage.pl?
turned into: http://www.new.site/somenewpage.pl??l??

So, I am not sure why I am getting foo.pl??l?? after the regex substitution. Also, any suggestions on how to change my blah.pl??l?? back into blah.pl?

Thanks Monks!

In reply to Regular Expressions and Question Marks by mr_dont

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