1. To run the previous command:
pwd /u/user/eucs/joe r pwd /u/user/eucs/joe
2. To re-run a command from the history list:
r 15
This re-runs command number fifteen from the history list.
3. To re-run the most recent command that starts with a particular string:
r grep grep -n '[dD]on't' tasks \ less
This re-runs the most recent command that starts with the string grep.