df - disk free. Lists disk[s] usage.

Uses fstab or equivalent to ID all 'disk' devices.

Lists :
Filesystem - lists mount points of devices.
1K-blocks - lists total size in 1K (1024) blocks. Option modifiable.
Used - how much is in use.
Available - how much is available.
Use% - use as a percentage.
Mounted on - directory assignment of Mount point.

Some Options :

-a - all, including dummies. 

-l - don't list network linked filesystems.

-i - list inode resources rather than file storage space.

-T - list filesystem's type. e.g swp, ext4


du - disk usage. Lists user's disk usage.

Lists directory and number of 1 K storage units used. Useful for locating
a directory holding a large amount of data.

Some Options :

-a - list usage for files also.

-B - use specified block size.
df -B 4K - lists as 4 K blocks.

-c - show a grand total at end.

--inodes - list inode usage rather than file.


quota - lists user's storage limits. Only avaiable for own account.

Lists : 

number of storage blocks user currently using.
quota - number of blocks which user can use for a limited time.
limit - maximum number of blocks, cannot be exceeded.
grace - time left for over quota usage.
number of files (inodes) user is currently using
quota - number of 'files' a user may have for a limited time.
limit - maximum number of 'files', cannot be exceeded.
grace - time left for over quota usage.


Options :

no option : just lists info on primary storage areas.
-v : lists info on all user storage areas.