MD5Hash 2.3 Now has /main command line switch. Only one param should be specified on the command line. Either the switch /main (not case sensitive) or the name of a file or folder.
When run with /main, MD5Hash attempts to set itself up as the "main instance" of the application. If it succeeds it will show MD5Hash Main in the caption bar instead of just MD5Hash.
With a Main instance running, if you select 20 files in Explorer, right click and choose MD5Hash in the context menu, each copy that loads will send the file or folder name to the main instance, then close, instead of getting one result in each copy.
If you want to have more than one copy running, for example if you have more than one physical hard drive and want to process a large file on each drive, simply start MD5Hash in the normal way with no Main copy running.
To start a Main copy, if you don't like command line, I recommend creating a shortcut with the /main after the exe name as in this Target line:
Note: when file or folder name is specified on the command line, do not wrap with quotes even if it has spaces. This will cause processing of that item to fail. The entire command tail is read as one string so quotes are not needed.
edit: Readme files updated.