Linux is very famous operating system and used everywhere in the world in most companies. The Linux is mostly black and white i.e most of the tasks are performed using CLI (Command Line Interface). You will have to remember commands to peform each and every action which makes Linux little difficult comparing to Windows Operating System.
Linux Operating such as CentOS is freely available which you can download and install on your computers or any virtual application such as VirtualBox. So If you have a PC or Laptop which has a Windows or MAC Operating System - then go on CentOS site and download CentOS ISO/Installer - then Install "Oracle VirtualBox" application - and then install CentOS Linux using CentOS ISO in your VirtualBox. Also it is recommended that you install putty software using which you can connect to Linux machine installed in VirtualBox or in any other computer in your network. If you are very beginner then get help from someone expert or use any existing Linux Machine.
Before we start there are following few basics which you need to know.
| File | Files contains some instruction/information. If you think everything in a operating system are files except folder/directory. |
|---|---|
| Folder | Folder is also known as Directory which is container used to contain/keep files or other folders. |
| Command | Command is an instruction that tells computer to perform some action or task. For example "date" command tell computer to display current date. |
| Script | Script contains one or more Commands used to perform one or more set of actions or tasks. |
| CLI | CLI (Command Line Interface) is an interface where tasks are performed using commands |
| Mount Point | Description |
|---|---|
| / | Top level root directory |
| /boot | Keeps booting files. |
| /root | Home directory of root user |
| /home | Home directory for all users except root |
| /bin, /usr/bin | Contain program files (basic commands) used by non-privileged users |
| /sbin, /usr/sbin | Contain program files (basic commands) used by super user (root) |
| /dev | Keeps list of available devices (hard disk, cdrom, pen drive). |
| /etc | Contain basic linux configuration files (user database, network configuration etc). |
| /lost+found | Contain orphan files |
| /mnt | Contain mounting point |
| /proc |
Contain system start information which is directly handled by kernel of Operating System (example: hard disk, CPU, RAM, Cache etc) |
| /tmp | Keeps temporary files |
| /usr | Keeps programs and data available to all users. |
| /var | Contain variable data, include log files and print spools etc on linux servers. or contains database of the server |
| /media | Mount point of removable devices like CDrom, pen drive etc. |
| /mnt | Temporary mount point for everything |