Small set of tools to interact with the user
Read input from the user
Ask the user to choose from a list of choices
Ask the user to answer by yes or no
Ask the user to enter something.
Returns what the user entered
Ask the user to enter a path to a program.
Look for it in PATH. If not found, ask the user to enter the full path.
If still not found, give up ...
Ask the use to enter path to a .app
Find the editor searching the environment, lastly ask the user.
Returns the editor.