I'm pretty new - came across this problem.  My webserver terminal is looking weird, there are some code echoes and then rows and rows of tilde. Where I type would be at the green square, but nothing I type commands or otherwise do anything.  Pressing enter jumps down the square and clears a tilde but does not make any difference.Tried to run clear screen commands ( ctrl-l and such ) doesn't do anything.  Searching about tildes just brings up the meaning of a tilde, not whatever this is.  Any way to kill what is happening?
Linux server terminal - rows of tildes, can't write commands?
command line;vi
You seem to be in Vi Editor editing mode (look down below the screen: -- INSERT --, is for insert mode).To change editing mode, you need to press ESC key first. And then to quit/exit vi altogether without saving you can type :q! and press ENTER.Vi is a widely used command line text file editor comes with almost every linux distros. You should take some time to learn it: How to Use the vi Editor