How to install VirtualBox guest additions in Ubuntu

When you have installed the Ubuntu operating system in VirtualBox you need to install the guest additions on it to solve the screen size problem and to install all important drivers.
Of course, it's too easy to install the guest additions in Windows, but we can't say the same for Ubuntu. Today I will show you how to do that.

Also Read: How to install Ubuntu in VMware

1) Start the Ubuntu in VirtualBox and then from "Devices" menu select "Insert Guest additions CD image...".
2) Now open up the terminal and execute the command given below.

cp /media/cdrom/VBoxLinuxAdditions.run /root/ 
chmod 755 /root/VBoxLinuxAdditions.run 
cd /root 
./VBoxLinuxAdditions.run

After it's done, simply restart your machine. And you can see the results.