Would I need to cite explanation of linux command lines?
Common Linux commands can typically be listed without introduction, when you're writing for Linux users.1 More advanced commands require introduction. As you've hinted, providing your own introduction is rather tiresome, because numerous introductions already exist. Hence, 


I suggest that you simply quote what others have said and provide a citation to the original.


Ideally, I'd recommend quoting man pages, since they are reputable, but you might have to rely on other sources when man pages provide insufficient detail.



1 What constitutes a common Linux command is rather vague. I'd certainly include cat, cd, and cp. I'd also include less and more. Thereafter I'd be a little hesitant, should grep, ps, ... be considered common?