To fix a broken terminal, try:

tput init
tput reset

If binary characters are sent to a terminal, it will often break because it interprets them as control characters. A random stream of control characters can make the terminal unreadable. You may not be able to see the commands as you type them until the terminal is reset.

To see the device of the current terminal:

tty

Pseudo-terminals under X are usually /dev/pts/?.

To see all current terminal settings:

stty -a