Linux Environment (Lec01, Lec02)

Hypervisor

hypervisor is virtual machine manager, can install multiple hypervisor , can create mutiple virtual machine in each virtual machine we can have different guest OS.

virtual machine can have 2 ways of S/W implementation 

1. System VM == execute program like physical machine , provide complete system platform

2. Process VM == disappear when process die (JVM)

 

username@hostname: /home/utubecar(~) $

internal command == whose code is part of the shell program itself. e.g) cd, exit, type, help

external command == whose code resides in a file on disk. e.g) ls, man 

 

/home is where users lies

 

Binaray directories == bin, sbin, lib ,opt

bin == user command directory

sbin == admin's command directory

opt == optional software 

Configuration directories == boot, etc

Data directories == home, root , srv, media , mnt, temp == contains user data

In memory directories == dev, proc , sys 

dev == contains file relate to your hardware // everything is file.

proc == contains process of PID running on linux 

Sysetm Resources directory == /usr/ == unix system resources

Variable Data directory == /var/

 

man [Command] == gives specific explanation about command

whatis [Command] == gives brief explanation abount command

whereis [Command] == use to locate binary soruce of command and man page of command 

the section of man page

man -k password == want to look for command that says something about password