While it's always nice to see a discussion about this, let me toss in
a piece of information:

IEEE Std. 1003-200x (the next revision of POSIX) will have a System V
influenced ps command in its XSI open group, so it'll make sense to
consider the implications for a moment. With the acceptance of that
standard in the forseeable future it might make sense to make an
implementation of this the 'default' utility, moving the existing
version into a non-default path; something like a /usr/ucb/ comes to
mind...  It's also worth noting that the echo utility will need a
similar treatment.

About supporting both BSD and System V style options in a single
executable: please take into consideration that there are at least
three command line options (-e, -p, -u) whose use differs between
'our' BSD implementation and System V.


-klaus