Filelight is a free, open source, simple, easy to use, and cross-platform KDE utility for viewing graphical disk space usage information. It works on Linux distributions and Windows operating systems. It is a disk analyzer that outputs your file system as a set of concentric segmented-rings to help you view disk usage.
The filelight package is available for installation in most if not all mainstream Linux distributions, you can install it using a package manager as shown.
$ sudo apt install filelight [On Debian/Ubuntu] $ sudo yum install filelight [On CentOS/RHEL] $ sudo dnf install filelight [On Fedora 22+]
Once you have installed fileflight, you can search for it in the system menu, and open it. You will land in the interface below, which shows all the mounted filesystems.