Can not input through bash terminal

Question

Very often I encounter this problem in my Debian VPS. When I type characters, the terminal refuse to display them. Instead I get a beep and shows outputs like

(arg : 4)
(arg : 5)
(arg :-1) 

And then, after a while the problem resolves automatically and I can resume typing. I'm wondering what can cause this problem? and how to counter it.

Thanks

Answer 1

If you press Esc and then some number or "-" and some number, bash will multiply your input by the number, e. g. pressing Meta+5 e will put eeeee on your command line. Before pressing e, the prompt will have been replaced by (arg: 5). So it's likely that your keyboard or some program is passing Esc/Meta(Alt) and numbers to your shell.