title: Replacing mutiple strings recursively within all files in a directory using Perl
body: <p>I'm new with perl. saw many samples but had problems composing a solution 
  I have a list of strings which each string should be replaced in a different string a->a2, b->b34, etc. list of replacement is in some csv file. need to perform this replacement recursively on all files in directory.
  might be any other language just thought perl would be the quickest</p>