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