In this step your goal is to add a command history to your shell. You want to have the following features:

1. Save all executed commands to the history.

2. Save the history to disk when the shell exits (to a file, .ccsh_history in the users HOME directory.

3. Reload the history from disk when the shell is started.

4. Support the built in command: history to list the command history.

That might look something like this:

ccsh> ls
Cargo.lock      Cargo.toml      src             target          test.txt
ccsh> pwd
/Users/johncrickett/dev/CodingChallengesFYI/challenge-shell/ccsh
ccsh> ls
Cargo.lock      Cargo.toml      src             target          test.txt
ccsh> history
ls
pwd
ls
ccsh> exit
ccsh %

Once you’ve got all that working - congratulations, you’ve built your own command line shell!