Ok, so when you have (-a | -b) it means that flag choice is not optional. Can we avoid trying to express valid flag combos in a single line and instead use multiple usage lines? In some cases, like in hwclock it is not a major issue and this can be left as is.
If people are in doubt they can refer to the manpage. My only concern is that this () pattern is not as wide-spread and confuses people. If others agree, we should sweep core existing core tools that use () and rework them.
