Almost entirely unrelated, but lately I worked with old photos that had missing, incomplete or wrong exif data. While trying to assess and automate fixing the collection via scripts, I used the command line utility "exif" a lot. You can't imagine how many times I typed "exit somefile.jpg" and flinched when the terminal window just closed. Guess I should just have created an alias but that's like resigning to your own stupidity. ;-)