Sorry, just a habit I have. I always redirect stdout (standard console output) to NUL (which is not a file, but simply a NUL device aka "the bit bucket") so that any console output from the "program" is hidden. I also redirect stderr (standard error or 2) to the NUL device as well. Programs can write their error messages to this this device (if they choose) and that just covers all the "output" bases. Handle 1 is stdin (standard input) and if the program runs silently, usually doesn't need to be redirected for these purposes.