Using `cd` with no arguments gives `TypeError`

[sepsol]

When executing just the cd command alone, I expect to be able to go to the $HOME directory of the current user. But instead I get this error:

[bright_shoes_9016@puter.com /bright_shoes_9016]$ cd
cd: TypeError: Cannot read properties of undefined (reading 'startsWith')

[AtkinsSJ]

Fixed by #45.