Ahh - I think I understand the question now (in the future, a few lines of the input file to serve as an example would be helpful). If I am getting this right, you need to read in the input file line-by-line, examine the line for path/filenames, and convert those filenames to short format. What have you tried? It seems fairly straightforward - perhaps split on whitespace and/or a regex to identify the path/filenames on each line. (It is hard to construct a good regex without knowing the format of the lines, so posting that will help.)