Analyze Disk Occupation
Why the hell is my HDD full again?
Run Disk Usage Analyzer (a.k.a. Baobab). Under Ubuntu it’s here: Applications -> Accessories. If not, then install
First, go to Edit -> Preferences. Here you can specify which drives to scan. (I have several large external HDDs that I don’t want to scan, so I just unticked them).
When you click on the button “Scan filesystem”, the previously selected drives will be scanned.
If you want to analyze your HOME folder, click on the button “Scan Home”.
Directories will be listed in descending order by size, so you can easily figure out which directories occupy much space. You can also use the chart on the right side to navigate in the directory structure.