Unix Basics

 

Below are some useful Unix commands: -

A directory is a collection of files, like drive or folder in windows.

The directory structure of a Linux machine is as below: -

/home --> home directory of the user.
/var    --> used to store log files are present here in folder /var/log.
/etc    --> used to store configuration files. Ex- /etc/puppet.conf  etc.
/tmp   --> used to store temporary files.
/opt    --> used to store/install third party software like java. By default, its used.
/lib     --> used to store library files.
/root   --> home directory of root. root is administrator of Linux machine and has highest privileges. 
/bin    --> to store binary files.
/dev --> to sore device files. e.g. /dev/sda , /dev/sdb etc.

When a user logs in to a Linux machine, automatically he will be in: -

/home/user1 directory
User1--> /home/user1
User2-->/home/user2
User3-->/home/user3

How to login a linux machine/server:-

To login you have provided with ip address, username, password.

To login we need a software called "putty". If you don't have you can download from google.

putty ==> to login a remote machine

ssh/telnet ==> protocol to be used

ip address or hostname

server1.in.ibm.com --> hostname

9.100.10.10 --> ip address

In earlier stage we have applications running in an operating system which is installed in a server.

application

os

server

Here the problem is there is CPU loss, memory loss. So we come up with below approach 

where we can have multiple machines can use the same operating system running in a single sharing server. These are called virtual machines.

vm1, vm2, vm 3

hypervisor

server