Write a script modify with the following syntax:
modify [-r] [-l|-u]
modify [-r]
modify [-h]
modify_examples
which will modify file names. The script is dedicated to lowerizing (-l)
file names, uppercasing (-u) file names or internally calling sed
command with the given sed pattern which will operate on file names.
Changes may be done either with recursion (-r) or without it. Write a
second script, named modify_examples, which will lead the tester of the
modify script through the typical, uncommon and even incorrect scenarios
of usage of the modify script.