1) Extract details for command options from man/help: https://github.com/learnbyexample/command_help/blob/master/c...
2) cut-like syntax for field manipulations with regexp, negative indexing, etc: https://github.com/learnbyexample/regexp-cut/blob/main/rcut
3) Simple calculator using python syntax: https://learnbyexample.github.io/practice_python_projects/ca...