http://redd.it/pii6j

#!/bin/bash

min=0 max=100

while true; do
    guess=$((RANDOM%(max-min+1)+min))
    echo Is your number $guess?
    select choice in Yes Lower Higher; do
        case $choice in
        Yes)
            echo Your number is $guess
            exit 0;;
        Lower)
            max=$guess;;
        Higher)
            min=$guess;;
        esac
        break
    done
done