Cmd-UpArrow in Terminal.app lets you jump to the last time you pressed enter.
Maybe there's a better official definition but it inserts a grey [ in front
of your prompt and that's the mark where you can jump back to.
[user@host $ seq 1 100 # START
1
2
3
...
98
99
100
user@host $ # press cmd-UpArrow here to jump to START
- cmd-k will delete screen + scrollback
- cmd-l will delete screen and not the scrollback
- there's a "Hard Reset" in the (searchable) help menu
Source: IRC, thanks jelly