How much of linux do i really need to know for HackTheBox or OSCP?

I am seeing some insane things running on linux boxes and im pretty sure that i need a proper training on Linux system administration to do these boxes, Is there a good youtube channel that covers Linux system administration in simple terms?

you need to know man and <mycommand> --help
then read commands for priv esc
and all the commands along the oscp pdf

  • overthewire did some good stuffs

Overthewire’s Bandit is recommended of course.

More of linux is understood by basically playing with it. Understanding things like dir structure, file permissions, commands etc.

Privesc is a completely different topic and can be studied by reading and watching material on linux privesc methods.