It all started when I couldn't run JDeveloper; the launcher didn't work, clicking on the icon in the /bin directory didn't work...WTF? I opened up a terminal and tried to open it there when I received a "hey, you've got no more room on your main drive (partition, whatever)"
I opened up DiskAnalyzer, started to just delete things I knew were gone (yeah, recipe for disaster, especially me). I used Synaptic to remove old or obsolete packages (Complete Removal). I removed a gigantic 3.3 GB log file from my /home directory. Yet System Monitor told me I had even less space now (no, you can't have less than zero, but I had gotten it up to a few hundred MBs of space).
Emptied the trash.
What about the root trash?
oraclenerd@oraclenerd:~$ su rootApparently that thing was quite full, I went from 100% "Used" to 45% used just like that. Yeah for me.
root@oraclenerd:/home/oraclenerd# cd ~
root@oraclenerd:~# cd .local/share/Trash/files/
root@oraclenerd:~/.local/share/Trash/files# rm *