- Added clarification comment of the DIR command
- Quoted `ARGS` usage required wrapping `ARGS` assignment in an array to properly expand. This wasn't broken before, but is required change to keep ShellCheck lint happy.
- Quote wrapped `DIR` usage, the volume target had an extra `/` before the `DIR` which seems unnecessary as `pwd` should return absolute path.
- Expanded `docker run` options to long-form.