Basic command line input

[Albus Dumbledore]

	I am trying to learn to run RHW3 from the command line. So far I have
had limited success, I am sure it is because I am making some sort of
basic error.
	I start by right clicking on the desktop and selecting "New Terminal"
from the pop up window that appearers. I have selected the command
"fsck" to try because it seem harmless if it goes arry.  It doesn't work
but it does return the following error message.

[albus at localhost albus]$ fsck -C
bash: fsck: command not found
[albus at localhost albus]$

What am I doing wrong?