!
Bash builtin to substitute with a command found in history.
TLDR
Substitute with the previous command and run it with sudo
$ sudo !!
Substitute with a command based on its line number found with history
$ ![number]
Substitute with a command that was used a specified number of lines back
$ !-[number]
Substitute with the most recent command that starts with a string
$ ![string]
Substitute with the arguments of the latest command
$ [command] !*
Substitute with the last argument of the latest command
$ [command] !$
