If we want to see all declared integer variables along with their values, then we must give the following command:
$ declare -i
This should produce the following output:
declare -ir BASHPID="" declare -ir EUID="1001" declare -i HISTCMD="" declare -i LINENO="" declare -i MAILCHECK="60" declare -i OPTIND="1" declare -ir PPID="1966" declare -i RANDOM="" declare -ir UID="1001"