In this step your goal is to implement a builtin command (cd) to change directories and pwd, to get the current working directory. The cd command has to be built in to the shell because it changes the internal state of the shell.

There are several other builtin commands you might have used regularly: cd, exit, export, pwd and unset. You can find the full list using the man pages for your shell - if you are not familiar with man, try it now with the command man man.

Once you’ve implemented cd and pwd you should be able to use them as so:

% ccsh
ccsh> ls
Cargo.lock      Cargo.toml      src             target
ccsh> cd target
ccsh> ls
CACHEDIR.TAG    debug
ccsh> pwd
/Users/john/dev/challenge-shell/ccsh/target
ccsh> cd ..
ccsh> pwd
/Users/john/dev/challenge-shell/ccsh
ccsh> exit
%