• Source 
    1. #
    2. #Accept numbers and perform addition, subtraction, division and multiplication. 
    3. #
    4. clear
    5. echo "Enter first number :"
    6. read number1
    7. echo "Enter second number :"
    8. read number2
    9.  
    10. echo "\n\n===== Available choices =====\n"
    11. echo "A - Addition"
    12. echo "S - Subtraction"
    13. echo "D - Division"
    14. echo "M - Multiplication"
    15. echo "E - Exit"
    16. echo "\n============================="
    17. echo -n "\nEnter your choice :"
    18. read choice
    19.  
    20.  
    21. while [ $choice != 'e' -o $choice != 'E' ]
    22. do
    23.     case $choice in
    24. 	[aA] )
    25. 		sum=`expr $number1 + $number2`
    26. 		echo "Addition of two number is "$sum
    27. 	;;
    28. 	[sS] )
    29. 		sub=`expr $number1 - $number2`
    30. 		echo "Subtraction of two number is "$sub
    31. 	;;
    32. 	[dD] )
    33. 		div=`expr $number1 / $number2`
    34. 		echo "Division of two number is "$div
    35. 	;;
    36. 	[mM] )
    37. 		mul=`expr $number1 \* $number2`
    38. 		echo "Multiplication of two number is "$mul
    39. 	;;
    40. 	[eE] )
    41. 		break;
    42. 	;;
    43. 	*)
    44. 		echo "Invalid choice"
    45. 	;;
    46. 	esac
    47. 	read temp
    48. 	clear
    49. 	echo "Numbers are :\n"
    50. 	echo "Number1 = "$number1
    51. 	echo "Number2 = "$number2
    52. 	echo "\n\n===== Available choices =====\n"
    53. 	echo "A - Addition"
    54. 	echo "S - Subtraction"
    55. 	echo "D - Division"
    56. 	echo "M - Multiplication"
    57. 	echo "E - Exit"
    58. 	echo "\n=============================="
    59. 	echo -n "\nEnter your choice :"
    60. 	read choice
    61. done
    62.