Also, gphoto2 is great for interacting with cameras using the command line. I will typically use it to import/backup all the images directly from a camera but it has so many more features. I believe darktable uses it behind the scenes, but it is extremely powerful on its own.
Another good command line program is dcraw, especially for batch developing RAW photos. These two programs probably make up more than half of my photography workflow.
Another good command line program is dcraw, especially for batch developing RAW photos. These two programs probably make up more than half of my photography workflow.