On Ubantu or Linux

13. What does the cut command do? Can you use it together with w to produce a list of login names and CPU times corresponding to each active process? Can you now (all on the same command line) use sort and head or tail to find the user whose process is using the most CPU?

14. Write a shell script which renames all .txt files as .text files. The command basename might help you here.

15. Write a shell script called pidof which takes a name as parameter and returns the PID(s) of processes with that name