Folders size

sudo du -hx --max-depth=1 /
=>
4.0K    /srv
28M    /home
16K    /lost+found
4.0K    /media
709M    /var
222M    /boot
6.1G    /usr
16M    /opt
44M    /etc
4.0K    /mnt
156K    /root
292K    /tmp
7.1G    /