I am trying to traverse the fp in `babashka`, and have found that running `(shell "cd ..")` in my script `bb-test` causes an error:

```
----- Error --------------------------------------------------------------------
Type:     java.io.IOException
Message:  Cannot run program "cd": error=2, No such file or directory
Location: /home/jack/Documents/clojure/leingit/./bb-test:120:1

```

Any ideas?