* Improved readability and corrected spelling.

* Minor cleanup of the "head" command.

* Updates to the "head", "tail", and "pwd" commands.

* Updated the "touch" and "cal" commands.

* Updates to the "df" command.

* Updates to the "help" and "factor" commands.

* Update 006-the-pwd-command.md

* Updating "uname" and "mkdir" commands.

Co-authored-by: Bobby Iliev <bobby@bobbyiliev.com>