Linux
Disk space explained
Paste the output of df -h and see in plain English what's full and how to find out where the space is going.
What does this mean?
The command df -h shows for each disk or partition how much space there is (Size), how much is used (Used), how much is available (Avail) and the percentage (Use%). Mounted on is the directory where the disk is located in your system. Here you see in plain English what is full and how to find out where the space went.
With ext4, 5% is reserved for root by default, which is why Avail can be smaller than Size minus Used. Everything stays in your browser. Getting a message like "No space left on device"? Paste it in the error message analyzer.