At the bottom of (info "(coreutils) Sorting the output") mention something like:
===Competing options=== Sometimes one gives "competing options" to ls, e.g., ls -lXS Well it turns out in the case of ls -lXS or ls -lSX, one will always get... There is no way to sort first via X and then via S within..., or first via S and then via X within... Please do mention something, else one gets wild dreams.
