Get Minimize, Maximize, Close Buttons in Gnome Shell Ubuntu/Linux Mint

In Ubuntu these buttons are not enable by default only close button is available, you can't minimize or maximize or restore any window in Gnome Shell.
But you can enable these buttons with Gnome Tweak Tool.

Install of Gnome Tweak Tool, Enter following command to install:

sudo apt-get install gnome-tweak-tool

Now open Gnome Tweak Tool.
See following screenshot to enable