Which is entirely dependent on how the shell is configured (not all shells have tab-completion for option flags, let alone path or command completion). I'm sure

Which is entirely dependent on how the shell is configured (not all shells have tab-completion for option flags, let alone path or command completion). I'm sure Vim or Emacs could do tab-completion for script flags, but you'd be in the same boat in the beginning: Someone has to script it first.