Recently I discovered, that via QPython console I can execute android (linux) commands. Ping works. Question is: how to interrupt it's output on smartphone? CTRL + C obviously isn't the answer.
There may be a way to send the modifier keys through the terminal app, however I have never used that app so I can't say. On Terminal Emulator you can long press the screen and send the control key from the pop up menu.
Also you could install Hackers Keyboard which includes a full desktop keyboard including control and alt keys.