[SOLVED] Csci 4100 assignment 3 writing a bash shell script

Write a bash shell script.
Required Reading
Linux – Chapters 8 and 10For this assignment you must write a bash shell script that keeps track of a list of email contacts by storing
them in a text file called contacts.dat. The source file should be called yourlastnameAssign3.sh, except
with your actual last nameYour program should present a menu to the user with the following options:
1. Add a contact
2. Remove a contact
3. Find a contact
4. List all contacts
5. Exit the programThe first option should prompt for a full name and check to see if there is already an entry containing this
name in contacts.dat. If there is already an entry for this name it should display a message indicating
that an entry already exists. If not, it should prompt for the email address, then add a line contacts.dat
containing the name followed by a comma, followed by the email address.The second option should prompt for a full name, then remove the any lines from contacts.dat containing
this name. The third option should prompt for a full name, then display any lines from contacts.dat
containing this name. The fourth option should display the contents of contacts.dat sorted by last name.The fifth option should exit the script
If the user chooses any of the first four options, once the action has been performed the menu should be
displayed again and the user should be prompted to make another choice.Helpful Commands and Options
Your shell script will need the file called contacts.dat to exist in order to work. If you execute the following
command at the beginning of your script:
touch contacts.datThis will create an empty text file the first time the script runs, and verify that it exists when you run the
script again.
The read command prompts for input and stores it in a variable. You can use the -p option to provide the
user with a prompt:
read -p “Enter your name: ” nameThis will store whatever the user enters in the variable name.
The grep command will display the lines in a file that match a given pattern. You can suppress the output
using the -q option if all you want is to determine if such a line exists:
if grep -q pattern file
then
# do stuff
else
# do other stuff
fiYou can display all of the lines that do not match a pattern using the -v option:
grep -v pattern oldfile > newfile
This is one way to remove lines matching a pattern from a file.
The sort command sorts a file alphanumerically by line. If you want to sort by a specific field of a file
containing a sequence of records, you can use the -k option:
sort -k 1 file # sorts by first field
sort -k 2 file # sorts by second field
Testing and Debugging Shell Scripts
The easiest way to debug a shell script is to test each command individually using the shell. If you want
to know the exit status of a command, you can display the special variable $?, which evaluates to the exit
status of the most recently executed command:
$ ls nosuchfile.txt
ls: nosuchfile.txt: No such file or directory
$ echo $?
1
If more substantial debugging is required you can run bash directly using the -x option:
$ bash -x hello.sh
+ echo ‘Hello World!’
Hello World!
All executed commands will appear in a line with a + at the beginning before they are executed.
2
Sample Run
Your output should look similar to the following:
Select one of the following options:
————————————
1. Add a contact
2. Remove a contact
3. Find a contact
4. List all contacts
5. Exit the program
Enter a choice (1-5): 1
Enter a name: Nicholas Coleman
Enter an email address: colemann@apsu.edu
Select one of the following options:
————————————
1. Add a contact
2. Remove a contact
3. Find a contact
4. List all contacts
5. Exit the program
Enter a choice (1-5): 1
Enter a name: John Nicholson
Enter an email address: nicholsonj@apsu.edu
Select one of the following options:
————————————
1. Add a contact
2. Remove a contact
3. Find a contact
4. List all contacts
5. Exit the program
Enter a choice (1-5): 4
Nicholas Coleman, colemann@apsu.edu
John Nicholson, nicholsonj@apsu.edu
Select one of the following options:
————————————
1. Add a contact
2. Remove a contact
3. Find a contact
4. List all contacts
5. Exit the program
Enter a choice (1-5): 1
Enter a name: Nicholas Coleman
There is already an entry for Nicholas Coleman
3
Select one of the following options:
————————————
1. Add a contact
2. Remove a contact
3. Find a contact
4. List all contacts
5. Exit the program
Enter a choice (1-5): 3
Enter a name: Nicholas Coleman
Nicholas Coleman, colemann@apsu.edu
Select one of the following options:
————————————
1. Add a contact
2. Remove a contact
3. Find a contact
4. List all contacts
5. Exit the program
Enter a choice (1-5): 2
Enter a name: Nicholas Coleman
Select one of the following options:
————————————
1. Add a contact
2. Remove a contact
3. Find a contact
4. List all contacts
5. Exit the program
Enter a choice (1-5): 4
John Nicholson, nicholsonj@apsu.edu
Select one of the following options:
————————————
1. Add a contact
2. Remove a contact
3. Find a contact
4. List all contacts
5. Exit the program
Enter a choice (1-5): 5
Thanks for using this program!
What to Hand In
Download the source file yourlastnameAssign3.sh to your local machine, then upload it to D2L in the
dropbox called Assignment 3.
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