please answer 6 for ubuntu terminal

4. Write a shell script that takes a command line argument and reports on whether it is directory, a file, or something else. 5. Write a shell script that accepts one or more file name as arguments and converts all of them to uppercase, provided they exist in the current directory. 6. Write a shell script that determines the period for which a specified user is working on the system. 7. Write a shell script that deletes all lines containing a specified word in one or more files supplied as arguments to it