* added head command

* Update 004-the-head-command.md

* added head command details

* Update 004-the-head-command.md

* Added documentation for tail command

* Update 005-the-tail-command.md

* Added documentation for netstat command

* Update 067-the-netstat-command.md

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