I really miss VMS. Adding a command wasn't just simply a matter of throwing an executable on the path, it had to be declared, with two options: One was to declare a command that had its own argument parsing or the better option, there was a way of doing external configuration of the arguments using (iirc) a .cld file which provided a way of specifying all the arguments and options for the command in a straightforward way. I did this for all the TeX programs around 1990 (I think this might have been the first TeX version which didn't use separate binaries for iniTeX vs TeX). It was nice because the OS automatically managed things like abbreviations so you only needed to type as much of a verbose command or option as was necessary for it to be unique. So while the command might have been `DIRECTORY /FULL` one could just type `DIR /FU` to get the same result. The VMS help system was also fantastic and allowed for easy browsing of available commands and their instructions in a way that man+apropos only approximates (not to mention that the tradition of using relatively verbose but understandable commands and options made it supremely usable.