One of the great ideas behind Unix is (was) that if you got an idea for a program, then you would first write it as a shell script - essentially calling a series of commands.
Then, if the program proved to be useful, you could improve on its interface, have users test it, and finally, when you were convinced it was worth it, write a "real" program.
This, of course, was before graphical user interfaces took over, so a "program" here is a CLI command in itself.
You still see this approach in some modern programs, especially if they show system information. Want to build a simple app to list all files in a folder? Just run
ls -al, parse the result and show it a table. Have fun with the various parameters, and you have your material for version 2.0