This single command is all you need for this task, but there’s an even shorter one that works well too. You can use the built in -t or –threshold option of the du command like this:
du -h -d 1 -t 1G /
It will display first level directories larger than 1GB within the root / path, just like the first command. If you want it to display all directories, not just first level, just leave out the -d 1 option.
You can sort the results from largest to smallest by piping in the sort command
du -h -d 1 -t 1G / | sort -hr