$ names=(missing older newer);echo '```';for op in -ot -nt;do echo;echo "# a $op b";echo;for a in "${names[@]}";do echo -n \|;for b in "${names[@]}";do echo -n " \`$a $op $b\` = ";test "$a" "$op" "$b";echo -n "$? |";done;echo;done;done
| missing -ot missing
= 1 | missing -ot older
= 0 | missing -ot newer
= 0 |
| older -ot missing
= 1 | older -ot older
= 1 | older -ot newer
= 0 |
| newer -ot missing
= 1 | newer -ot older
= 1 | newer -ot newer
= 1 |
| missing -nt missing
= 1 | missing -nt older
= 1 | missing -nt newer
= 1 |
| older -nt missing
= 0 | older -nt older
= 1 | older -nt newer
= 1 |
| newer -nt missing
= 0 | newer -nt older
= 0 | newer -nt newer
= 1 |