Check Linux disk usage

Some ways to see what is filling your disks:

du --max-depth=5 -xha | sort -hr | head -n 30

Or install ncdu (http://dev.yorhel.nl/ncdu):

ncdu -rx /
ncdu 1.10 ~ Use the arrow keys to navigate, press ? for help     [read-only]
--- / ----------------------------------------------------------------------
  817.0MiB [##########] /usr
  486.3MiB [#####     ] /var
  476.5MiB [#####     ] /lib
   64.6MiB [          ] /boot
   19.8MiB [          ] /root
   11.1MiB [          ] /sbin
    9.5MiB [          ] /bin
    5.3MiB [          ] /etc
e  16.0KiB [          ] /lost+found
    8.0KiB [          ] /media
    4.0KiB [          ] /lib64
e   4.0KiB [          ] /tmp
e   4.0KiB [          ] /srv
e   4.0KiB [          ] /opt
e   4.0KiB [          ] /mnt
e   4.0KiB [          ] /home
@   0.0  B [          ]  initrd.img.old
@   0.0  B [          ]  initrd.img
@   0.0  B [          ]  vmlinuz.old
@   0.0  B [          ]  vmlinuz
>   0.0  B [          ] /sys
>   0.0  B [          ] /run
>   0.0  B [          ] /proc
>   0.0  B [          ] /dev
Total disk usage:   1.8GiB  Apparent size:   1.8GiB  Items: 112384

The '-x' option makes sure it only counts files on the same filesystem as the directory being scanned. The '-r' option enabled read-only mode so you can't accidentally delete file/directories.

Press enter on a directory to drill down deeper in to the filesystem to see exactly what is using disk space.