I used OS-9 on a 68K system when I worked for a telecom company. It was a great OS. The one thing I remember loving was typing `cd ...` to go up to the parent's

I used OS-9 on a 68K system when I worked for a telecom company. It was a great OS. The one thing I remember loving was typing `cd ...` to go up to the parent's parent directory. I still find myself typing it in bash and being disappointed it doesn't work.