関連ワード:  write a shell script    write a shell script to find factorial of a number    write a shell script to find the factorial of a given number    write a shell script to add two numbers    write a shell script to reverse a number    write a shell script to find greatest of three numbers    write a shell script to reverse a string    write a shell script to print fibonacci series    write a shell script to find the power of a given number    write a shell script to print a message