On 3/19/24 08:33, Rafal Maszkowski wrote:
he --debug option advised in README does not say anything helpful:(echo a; echo b) | sort --debug -nu sort: text ordering performed using simple byte comparison a ^ no match for key
That diagnostic message is helpful. It's telling you that there's no number, so everything sorts as being the same, which means 'sort -nu' (correctly) outputs just one line.
'sort' has behaved this way for quite some time, and POSIX requires this behavior.
