Saving this to a file and checking it after the run is an excellent idea. It will tell you what input file was used and what process it is simulating. More importantly, it will have warning and error messages. Most common are ctp errors (unregistered variable warnings) when you have a variable in the input file that it does not recognise. If you have a typo in your input file, it will create a variable corresponding to what you typed in, and assign it the value you gave it, but this will be totally ignored by the fortran code. A warning of this kind means that one of the input file variables was not set, and while SIMC may still run fine, it may generate garbage results. Also, SIMC will warn you of unusual options, and let you know if it decides to override any of the flags or parameters you give it. It is often hard to check all of this when you run SIMC, because under some conditions you will get hundreds of error messages during the event generation. It only shows these for the first 5000 events, but this can be plenty to push the important messages far off screen.