One missing for me: when doing anything with numbers, use shell arithmetic $(()) and (()) instead of [[]] to be explicit: https://tldp.org/LDP/abs/html/arithexp

One missing for me: when doing anything with numbers, use shell arithmetic $(()) and (()) instead of [[]] to be explicit: https://tldp.org/LDP/abs/html/arithexp.html https://tldp.org/LDP/abs/html/arithexp.html