I am, but I wrote that. Something like "ps -axu" will fail the UNIX/POSIX/SysV parsing, then restart in a pure BSD mode with the "-" ignored. Something like "p

I am, but I wrote that. Something like "ps -axu" will fail the UNIX/POSIX/SysV parsing, then restart in a pure BSD mode with the "-" ignored. Something like "ps -aux" will too, unless there is a user named "x". There is also a PS_PERSONALITY environment variable to force the parser to act in a particular way. It was needed to transition people over to a standards-compliant syntax. I couldn't support all the old syntax. Prior to 1997, something like "ps -ef" would parse as "ps ef" does today, which is not standards-compliant. People were unwilling to just switch over without the compatibility hacks. There were instances of things like "ps -aux" all over the place, including in people's private shell scripts. People couldn't resist typing it. I got pushback just for including the warning on stderr when somebody caused the parser to kick in to compatibility mode.