Playing around with a Raspberry PI I came to need this info. Here is the command:
You should see something similar to this:
pi@raspberrypi:~ $ df -h Filesystem Size Used Avail Use% Mounted on /dev/root 26G 6.5G 18G 27% / devtmpfs 334M 0 334M 0% /dev tmpfs 463M 0 463M 0% /dev/shm tmpfs 463M 6.4M 456M 2% /run tmpfs 5.0M 4.0K 5.0M 1% /run/lock tmpfs 463M 0 463M 0% /sys/fs/cgroup /dev/mmcblk0p6 253M 53M 200M 21% /boot tmpfs 93M 0 93M 0% /run/user/1000
The option -h displays the size units which makes it easier to read for humans, hope it helps.