This isn't an installation question....

But try:

cd /usr/bin
cd /bin
cd /usr/sbin/
cd /sbin

"UNIX for dummies" is actually a pretty good book to get if you need basic help with UNIX commands.

But be careful, the terminal is a very powerful, and dangerous, tool.
If you ever learn one command in the terminal... it should be 'man'

For example:

cd /bin
ls -l
man talk

those are lowercase "L" by the way.

The Terminal gives you access to the standard POSIX commands that you will find in most UN*X systems. Some of the more basic ones are:

ls (list files)
ls -l (list files with details)
cd (change directory)
pwd (display current directory)
man (show manual page)
I've been asking the same question to myself, and i spend quite a while searching for the answer on the web. But i've finally succeeded :) you just have to type this in terminal.app :

man tcsh

This is because tcsh (TC shell) is the shell that's terminal is using.
Now you just <optionnal>hit space until all is displayed, select it all, choose 'Save the selected text as' in the 'File' menu, then open it using 'Textedit' and then</optional> search for chapter 'Reference' (about the middle) where all the builtin commands are described.
i've just discover a faster way to do it, type


which will list you all the builtin commands and then

man <command>

To know what this command means.

PS : not every command has a 'man' so for further details you have to do as explained in my previous post.