$ sudo !!- run the previous command with superuser privileges.
$ cd !$- the “!$” is a shortcut for the argument used in the last command. So if you create a directory in one like using mkdir, you can type this command to change to that directory without needing to type out the whole directory name. Handy!
$ !cd- re-run the most recent command starting with “cd”.
$ ^save^dave^- re-run the previous command, replacing the first instance of “save” with “dave”.
$ CTRL-r- search backwards through your commands (great for re-running a recent command).