Creating a calculator script

Question

I am trying to make a calculator with a bash script. The user enters a number, chooses whether they wish to add, subtract, multiply or divide. Then the user enters a second

Answer 1

!/bin/bash

PS3="what's the operation? " declare -A op=([add]='+' [subtract]='-' [multiply]='*' [divide]='/')

while true; do read -p "what's the first number? " n1 read -p "what's the second number? " n2 select ans in "${!op[@]}"; do for key in "${!op[@]}"; do [[ $REPLY == $key ]] && ans=$REPLY [[ $ans == $key ]] && break 2 done echo "invalid response" done formula="$n1 ${op[$ans]} $n2" printf "%s = %s\n\n" "$formula" "$(bc -l <<< "$formula")" done