Problem
1. Write a program that uses a filename as argument and displays its contents in uppercase.
2. Write a program that
(i) creates a file foo with permissions 666 and a directory bar with permissions 777,
(ii) removes foo and bar.
3. Write a program that accepts a directory name as argument and creates it if it doesn't already exist. If there is an ordinary file by that name, the program should remove it before creating the directory.