What is a version control system? How is Git useful?

Question

like for example i am doing ruby on rails and using git for version control.

Answer 1

The best part about Git is unlike other source control systems, Git can work offline. Doesn't matter whether you are on a plane or at home or some distant place with no connectivity. You can still commit changes to your local git repository & push it to centralized server (if you have one) when you are connected. One more thing which makes Git very powerful is 'Branches'. If you want to do a bug fix or want to try something new without harming your current working code, just create a branch & work on it. When things ae working fine in your branch, you can merge it to the master branch.

I would say Git provides more flexibility than anything other SCM.