Here’s one from the Apple Gazette.
This comes really handy when moving files to an external drive for backup or transfer. So you copy them to the new destination and delete the ones in the original machine. But here’s a way to make this faster:
If you press Command when you drag those files as soon as the transfer is complete, they will automatically delete from the original source. This can be a real time saver if you’re moving a lot of files onto an external drive.