Thanks for your reply, will try that way i.e to write a third file to manage two files. However just for information, I am trying to simuilate the application synchronization using perl, where everytime an application is launched it will download the config file first and will check is there is version mismatch of local copy with that of the repository copy(which is uploaded on some webpage) and if there is a mismatch it will download the newer version. I am bit afraid having the third file will slove this issue as I may need to launch the third file from the first exe.