portable testing tool for Unix command lines

 Clitest is a portable POSIX shell script that performs automatic
 testing in Unix command lines. This script was carefully coded to
 be portable between POSIX shells.
 .
 It's the same concept as in Python's doctest module: you document
 both the commands and their expected output, using the familiar
 interactive prompt format, and a specialized tool tests them.
 .
 The clitest command searches for pieces of text that look like
 interactive Unix command lines, and then executes those command
 lines to verify that they work exactly as shown.