Run these exercises on uisacad5. Create a folder named assignment2 and write the first three programs listed below. Your grade will be based only on the first three exercises only but please do the observe the behavior of each command. Make sure you follow the guidelines for submitting assignments as described in the Course Syllabus. Exercises 1. Write a program called nf.sh to display the number of files in your current directory 2. Write a program called whos.sh to display a sorted list of the logged-in users. Just display the usernames and no other information. 3. Write a program called twice.sh that takes a single integer argument and double its value Example /twice.sh 15 30 /twice 0 4. Given the following variable assignments y ? z-one two three now-s> And these files in your current directory: names test1 u vv zebra What is the output of the following commands? Secho error $echo $x Secho "Sy" Secho $z wc-I Secho "Sz wc -l Secho Snow Secho hello Ssymbol out Secho " Secho 'ls 5 4> 18? Secho Secho IS$symbol Secho $Ssymbol