Do you know of any businesses that run from the command line? What I mean is that most, if not all, employees interact with the company's computer systems over the command line rather than through GUI applications. They build shell scripts at the group/team level to extend the functionality of their software, rather than waiting for the central IT team or a consultant to build those features in the GUI app.

A friend runs a small warehouse and installation operation, and he was describing the cobbled mess that is their operational software stack (inventory management, scheduling, etc). I immediately thought of the UNIX philosophy and am wondering if it has been successfully deployed broadly at companies out there.

  This is the Unix philosophy: Write programs that do one thing
  and do it well. Write programs to work together. Write programs
  to handle text streams, because that is a universal interface.[1]

I wasn't around in the '70s and '80s, so I don't have the experience of the workplace prior to widespread GUI deployment, but I assume many companies did just this. Now GUIs (and Web-based software) dominate the workplace software world. The problem is that these custom enterprise stacks are usually half-baked (reference hundreds of HN comments here), so everyone is less productive and ugly hacks are bolted on to the stack.

[1] https://homepage.cs.uri.edu/~thenry/resources/unix_art/ch01s06.html