For this exercise I wanted to give you some real-world examples of useful bash scripts. Therefore, you will write a couple of scripts that I actually use in my teaching to automate clerical tasks. To begin, please copy this (ficitious) classlist.txt to your directory, and note that it contains a list of usernames.

bholly

bjones

bscott

dgatton

dhathaway

jbonham

jcroce

jdenver

jhendrix

jjoplin

jmorrison

kcobain

mhutchence

oredding

pcline

rbuchanan

rrhoads

rwaters

svaughan

wwilliams

Write a script called addnames that is to be called as follows, where classlist is the name of the classlist file, and username is a particular student's username.

./addnames classlist username

The script should

1. print a message stating that the name already existed, or

2. add the name to the end of the list.

 Hint: Use a for-loop to process each line in the file. To create a list of lines in the file, remember that you can use any bash construct inside a script that you can use in the terminal window. How would you list the lines of the file in the terminal window? Similarly, how would you append a particular item to the end of an existing file from the terminal window?