The history command will display a listing of the most recent keyboard
input.
Example, when you type #his, yTin will show:
0 #help verb
1 #cr ?
2 test
3 help
4 say yes?
5 reply no
6 #his
Then !3 will send "help" to mud, !1 will send "#cr".
You can also type "!sa", this will search back and send "say yes?".