If you do not know what is GIT, you are missing one of the best revision control systems on the internet. It can handle all types of your work, be it programming, designing, or any casual work.
Git was initially designed and developed by Linus Torvalds for Linux kernel development in 2005.
Installation:
# Ubuntu/Debian
sudo apt-get install git
# CentOS/Fedora
sudo yum install git
# Configure:
git config --global user.name "Your Name"
git config --global user.email "your@email.com"
# Create your first repo:
mkdir myproject && cd myproject
git init
git add .
git commit -m "Initial commit"