Hi Ludo, thanks.
I can confirm that this works! I'm using it to regularily call fstrim (one has to regularily call fstrim on SSDs) so the mcron behaviour of, if an appointment was missed, doing it at the first next availability is good for regularity. The man page says that trimming once a week is good. Longer term maybe there should be a way of specifying that a filesystem should be trimmed in a "file-system" specification. Note that fstrim expects the filesystem to be mounted for it to work.
