di vs df

xbmc@xbmc-P35C-DS3R:/content2$ di
The program 'di' is currently not installed.  You can install it by typing:
sudo apt-get install di
xbmc@xbmc-P35C-DS3R:/content2$ sudo apt-get install di
[sudo] password for xbmc:
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following NEW packages will be installed:
  di
0 upgraded, 1 newly installed, 0 to remove and 4 not upgraded.
Need to get 40.9 kB of archives.
After this operation, 141 kB of additional disk space will be used.
Get:1 http://au.archive.ubuntu.com/ubuntu/ precise/universe di i386 4.30-1 [40.9 kB]
Fetched 40.9 kB in 0s (71.4 kB/s)
Selecting previously unselected package di.
(Reading database ... 158889 files and directories currently installed.)
Unpacking di (from .../archives/di_4.30-1_i386.deb) ...
Processing triggers for man-db ...
Setting up di (4.30-1) ...
xbmc@xbmc-P35C-DS3R:/content2$ di
Filesystem         Mount               Size     Used    Avail %Used  fs Type
/dev/sdc1          /                 687.7G     4.2G   648.6G    6%  ext4
/dev/sdb2          /content          688.6G   687.4G     0.1G  100%  btrfs
/dev/sda1          /content2         458.5G   181.9G   253.3G   45%  ext4
udev               /dev                2.0G     0.0G     2.0G    0%  devtmpfs
tmpfs              /run              806.0M     0.9M   805.1M    0%  tmpfs
xbmc@xbmc-P35C-DS3R:/content2$ df -h
Filesystem      Size  Used Avail Use% Mounted on
/dev/sdc1       688G  4.2G  649G   1% /
udev            2.0G   12K  2.0G   1% /dev
tmpfs           806M  888K  806M   1% /run
none            5.0M     0  5.0M   0% /run/lock
none            2.0G  280K  2.0G   1% /run/shm
/dev/sdb2       689G  688G   68M 100% /content
/dev/sda1       459G  182G  254G  42% /content2