Ctrl-C:  sends the kill signal "SIGINT" to terminate the program.

Ctrl-Z:  sends the stop signal.    Restart the program in the foreground with fg and restart it in the background with bg.  Use jobs to list all background programs.  Ctrl-Z sends SIGSTOP, which freezes the program. To restart it from the same point, you need somehow to send a SIGCONT. This can be done by using the commands fg (to restart it as a foreground process) or bg to restart it in the background.

(Ctrl-Y:  same as Ctrl-Z, but stops the program only when it tries to read user input from the console)

Ctrl-S:  scroll lock, to pause output when too much output is scrolling quickly.  Then use Shift-PgUp and Shift-PgDn to scroll.

Ctrl-Q:  resumes output that was paused with Ctrl-S.

Ctrl-L:  clear the screen and put the prompt in the top left corner.  Useful for if the screen becomes garbled.  Sometimes it doesn't work (like after running 'cat /bin/bash') and so type "reset" (without quotes, even though the word "reset" won't appear right) and hit enter.

Ctrl-D: signals EOF  (end of file)