As a Linux administrator there will be times when you go in blind and do not know why system you are logging into, one way to CSI your way through the system is with the fd and fdisk command.  Which will tell you who murdered Sideshow Bob.  Not really it will just tell you the systems disk information and the partition it has.  The first command you can run is the df command, if you run it by itself it would look a little cryptic.  So most of the time you will see people run it with the -h option

The df command which is an abbreviation of the words disk free is a command used to display the amount of available disk space for file systems.  It gives you amount of disk space available for each mount points.

The next command you can run is the fdisk command, as with df if you just type fdisk by itself, you won't get anything useful.  So you usually see it with the -l option

fdisk gives you the disk partition information as you can see we have two partitions and mount points, the first is a boot partition which does not have a lot of space which it does not need a lot of space.  The second partition has the bulk of space and is the system that we as users and administrators interact with.  It also tells you the swap size and mount points.  The home sector is also shown, you will often see the system administrator use this command when the system is running out of space.