Updated cli docs

book/src/cli-usage.md

@@ -35,11 +35,13 @@ There is a set of special commands that only work in interactive mode:
 
 | Command | Action |
 |---------|--------|
-| `list`, `ls` | List all functions, dimensions, variables and units |
+| `list` | List all functions, dimensions, variables and units |
 | `list <what>` | Where `<what>` can be `functions`, `dimensions`, `variables`, `units` |
 | `info <identifier>` | Get more information about units, variables and functions |
 | `clear` | Clear screen |
 | `help`, `?` | View short help text |
+| `save` | Save the current session history to file `history.nbt` in the current directory |
+| `save <dst>` | Save the current session history to file `<dst>` relative to the current working directory |
 | `quit`, `exit` | Quit the session |
 
 ### Key bindings