Summary : Disk Usage Analyzer (aka Baobab)

Description :
Disk Usage Analyzer is is a graphical, menu-driven application to analyze
disk usage in any Gnome environment. Disk Usage Analyzer can easily scan
either the whole file-system tree, or a specific user-requested directory
branch (local or remote).

It also auto-detects in real-time any changes made to your home directory
as far as any mounted/unmounted device. Disk Usage Analyzer also provides
a full graphical tree-map window for each selected folder.

URL : https://wiki.gnome.org/GnomeUtils/Baobab
License : GPLv2+