Ubuntu Fdisk is full

I can not use the Chinese input method, so bad, but I had to memorize some stuff about using Ubuntu,

Yesterday I found I can not login to my Ubuntu system, I donnot know why, so search all q/a in website, some advice listed:

1. Environment is wrong, directory in Etc/profile, etc/env, ETC/BASHRC

2.system disk is full

I am pretty sure my question is 2. So I went to recovery mode to check my diskspace,but under root user no file and command can not use, file is ReadOnly, Command no authority,fuck.so search website again, oh, god there is a command can change this: "Mount-o remount, rw/", no W I can use everything

Second, where to found my big file which stuck the whole memory, just CD/

Df

Ls-l

And I found directory/var/log/cups are so big,

So I use the RM to del these log files. And then I can login my ubuntu again, till now, I made it.

Ubuntu Fdisk is full