Linux Shell scripting

Student Email List Write a script named adds tudent.sh that maintains a list of student email addresses in a file namedclasslist.txt. The script should Create the classlist.txt file if it doesn't exist . If the command is invoked without arguments, it should provide the user with usage information . The command may be invoked with one or more email addresses, and will add each to the classlist.txt file . If an email address already exists in c lasslist.txt, it will not be added twice, and the user will be given notice that the email address is already present $ ./addstudent.sh Usage: addstudent.sh [email-address]... $ ./addstudent.sh student1@fullcoll.edu classlist.txt isn't writable $ chmod tw classlist.txt $ ./addstudent.sh student1@fullcoll.edu $ ./addstudent.sh student2@fullcoll.edu $ ./addstudent.sh student1@fullcoll.edu studentl@fullcoll.edu is already in list ./addstudent.sh student3@fullcoll.edu $ ./addstudent.sh student4@fullcoll.edu student5@fullcoll.edu $./addstudent.sh student3@fullcoll.edu student3@fullcoll.edu is already in list $ cat classlist.txt student1@fullcoll.edu student2@fullcoll.edu student3@fullcoll.edu student4@fullcoll.edu student5@fullcoll.edu