Suppose you have a path to a file, for example /Users/flavio/test.txt.

Running

basename /Users/flavio/test.txt

will return the text.txt string:

If you run basename on a path string that points to a directory, you will get the last segment of the path. In this example, /Users/flavio is a directory:

The basename command works on Linux, macOS, WSL, and anywhere you have a UNIX environment