How to use UNICOS?
It is a UNIX variant, so many of the usual commands work. You have bash for a shell, midnight commander as a file manager.
For programming, make, cc, CC, as, f90 and ld are your friend.
The interactive debugger (best with X11) is called totalview.
There is vi, vim and emacs for editing files.
There’s a visitor’s log book to append to.
via this interesting blog post about a timing bug which knocked the simulator out for a while: “Recently, I’ve noticed that the C compiler hung in the simulator.”