Shell Programming and Scripting

read -p "Enter the two digits of your sum: " NUM1; read -p "+" NUM2

Enter the two digits of your sum: 5
+ 7

Enter the two digits of your sum: 5 + 7

read -p "Enter an operation: " NUM1 OP NUM2
echo "$NUM1 $OP $NUM2"
echo $(( $NUM1 $OP $NUM2  ))

printf "Enter the two digits of your sum: "
## get cursor position
echo -en "\E[6n"
read -sdR posn
posn=${posn#*[}
col=${posn#*;}    # extract column
read NUM1
tput cuu1         # move up, then right
tput cuf $(( $col + 1 ))
printf "+ "
read NUM2
echo "$NUM1 + $NUM2"

#!/bin/bash
stty -echo
read -p "Enter the two digits of your sum: " NUM1
stty echo
read -p "$NUM1 + " NUM2
echo "The sum of $NUM1 + $NUM2 is $((NUM1 + NUM2))."

echo -en "enter num: \e7"; read N1; echo -en "\e8$N1 + \e7"; read N2; echo -e "\e8$N2 =" $((N1 + N2))
enter num:  12 + 13 = 25