the environment Terminal uses by default is BASH. Try looking for bash or unix command line tuturials on the internet.
some basics:
man - typing man followed by a command will give you a manual for that command
ls - list files and folders in current folder
cd - change directory
rm - remove file (can be QUITE dangerous)
mv - move / rename file
host - used to find the ip address of a website
whois - find out who owns a website