Du-c9 invalid flags error



I’m very near my disk space limit in my workspace (9.3M), but my project folder is very tiny. I’ve been trying to understand what is taking up the rest of the disk space, but I can’t seem to find anything. Does anyone else have experience of their disk filling up too fast, and how would you go about finding what the issue is without using the du-c9 command? The du-c9 command only sends an invalid flags error when I run it.