Display free disk space using df

---

$ df
Filesystem     1K-blocks      Used Available Use% Mounted on
/dev/sda1       47931368  18992880  26480628  42% /
none                   4         0         4   0% /sys/fs/cgroup
udev             2009680         4   2009676   1% /dev
tmpfs             404732      1276    403456   1% /run
none                5120         0      5120   0% /run/lock
none             2023660       144   2023516   1% /run/shm
none              102400        28    102372   1% /run/user
/dev/sda5      413296896 371702128  20577416  95% /home