clear sum=0 i=\"y\" echo \" Enter one no.\" read n1 echo \"Enter second no.\" read n2 while [ $i = \"y\" ] do echo \"1.Addition\" echo \"2.Subtraction\" echo \"3.Multiplication\" echo \"4.Division\" echo \"Enter your choice\" read ch case $ch in 1)sum=\`expr $n1 + $n2\` echo \"Sum =\"$sum;; 2)sum=\`expr $n1 - $n2\` echo \"Sub = \"$sum;; 3)sum=\`expr $n1 \\* $n2\` echo \"Mul = \"$sum;; 4)sum=\`expr $n1 / $n2\` echo \"Div = \"$sum;; *)echo \"Invalid choice\";; esac echo \"Do u want to continue ?\" read i if [ $i != \"y\" ] then exit fi done OUTPUT *********** [04mca58@LINTEL 04mca58]$ sh calculator.sh Enter any no. 121 Enter one no. 21 Enter second no. 58 1.Addition 2.Subtraction 3.Multiplication 4.Division Enter your choice 1 Sum =79 Do u want to continue ? y 1.Addition 2.Subtraction 3.Multiplication 4.Division Enter your choice 2 Sub = -37 Do u want to continue ? y 1.Addition 2.Subtraction 3.Multiplication 4.Division Enter your choice 3 Mul = 1218 Do u want to continue ? y 1.Addition 2.Subtraction 3.Multiplication 4.Division Enter your choice 4 Div = 0 Do u want to continue ? n