A. when the shell script is executed the program ask the user for input and the variable is initialized.
B. To execute the shell script use terminal of Ubuntu OS, change the working directory to Desktop, set read and execution permissions.
C. VERBOE variables are used to print out the output along with the commands that are used to print them out. VERBOSE is by default off in shell script.
D. the program runs as long as no syntax error is encountered and after taking all the inputs it terminates.
E. To get input from the user “echo” command has been used.
F. To handle the input of different data type “while” loop has been used to make sure a user enter proper data type. For example the “while” loop for variable “studenName” accepts alphabetic letters and space and “while” loop for the student’s marks accepts digit values. If the user enter invalid data type a message will be displayed asking for proper data type and valid range for that variable.
G. By running the shell script again new records will be added to CSV file without changing already saved data.