Exit - add exit
in the script will terminate the script
#! /bin/bash
echo "line 1"
echo "line 2"
echo "line 3"
read -p " How old are you? " age
if [ $age -lt 0 ]; then
echo "you cannot have negative age!"
exit
#if we get negative, programe exit here. if positive, programe will continue.
fi
echo "line 4"
echo "line 5"