We will use the file classlist.txt. Note that it contains a list of usernames. 3. Write a script called finduser that is to be called as follows, where classlist is the name of the classlist file, and...

Extracted text: We will use the file classlist.txt. Note that it contains a list of usernames. 3. Write a script called finduser that is to be called as follows, where classlist is the name of the classlist file, and username is a particular student's username, either first name or last time. ./finduser classlist username The script should check that the correct number of arguments was received and print an error message if not, check whether the classlist file exists and print an error message if not, print the line of the given username in the classlist file If you have not been doing so all along, you should now add some comments to your script and thoroughly test it! 4. Write the script into your lab report.