In the first exercise, I used the Up arrow to navigate through previously used commands to execute the ps u command.
In the second exercise, I used the !! command to run the previously used command.
In exercise 3 I navigated to the directory module-one-practice. Then I used the command cd .. to navigate back to the parent directory.
Then I executed the cd !$ which executes cd .. when sends me to the home directory.
In exercise four I executed the history command which listed all of the commands executed. I then executed the command !238 238 is the number in of the command in the history list.
