If you’ve been around long enough to have used Microsoft DOS as your primary operating system, you might remember Norton Commander.
Norton Commander 5.51 running on MS-DOS 5
Managing files in DOS was a pain in the butt without something even remotely graphical. I loved the two panes and simplistic navigation in folders. In fact I think Norton Commander made me better at command line stuff after I got a visualization of the file structure.
After I got into Linux/Unix/Mac OS X I was so tickled when I found Midnight Commander. MC is a port (only visually) of the original Norton Commander. It’s awesome and I’ve used it for years.
Midnight Commander 4.8.13 running on Mac OS X 10.11.1
Recently I found a replacement for Finder on Mac OS X that looks shockingly similar. It’s called Commander One.
Midnight Commander is free and open source – which means you can dig into how it works and help fix bugs you might find. It’s a pretty stable product though and still actively worked on. Commander One is free but not open source. There are “Pro packs” you can purchase to add additional functionality.