Essential Resources:

Secure Access su [options] [username]

SSH key gen for secure access :

linux directory tree: bin , boot , dev , etc, proc, /, home, mnt, sbin

Basic Shell commands whoami, cd , apropos ,ls cp ,mkdir,touch,cat,mv, cp,pwd, locate, find, which,vi,vim, gedit,comm ,diff, vimdiff,man

Checking Manual of commands man man -k passwd apropos passwd apropos partition