du -h --max-depth=1 / | sort -h -r
du -h --max-depth=1 / | sort -h -r This will show each folder in / including / itself.
Mind that this could take a long time to scan through all the files. If you require any specific sizes of the subfolders in a folder, specify the exact path of the folder instead of / or just skip / if you're already in that folder.
-hoptions shows sizes in human friendly format--max-depth=1instructs command to go only 1 directory deep inside/sort -h -rsorts results using human friendly sizes and-rinstructs command to show results in reverse order (from largest to smallest directories)