Well, you can't, as far as I know. This doesn't seem to be a program that have its output redirected using DOS.
But there's nothing stopping you from reading the 'progress.cfg' file directly and getting the information that way. ProTools already does it - look at the second icon on the ProTools palette (the magnifying glass with the letter i).
This runs a procedure called '_procfg.w' which is usually stored in the procedure library dlc\src\protools.pl. Extract the file from the library and have a look at the Get_CFG internal procedure to see how it reads the .cfg file and extracts the same information as shown by 'showcfg.exe'.
HTH