when using the web based SSH terminal provided by the Plesk interface, there is no way to copy the text from the terminal since it is a canvas element. This script will allow to use Ctrl-Shift-C to copy instead of opening developer tools

Ctrl-Shift-C-Should-Copy.js

/* Intercept and check keydown events for Ctrl+Shift+C */

document.body.addEventListener('keydown', function(evt){
	if (evt.ctrlKey && evt.shiftKey && evt.key == "C"){
		// Copy the selection to the clipboard
		document.execCommand('copy');
		// Throw away this event and don't do the default stuff
		evt.stopPropagation();
		evt.preventDefault();
	}
}, false);

/* Intercept and check keyup events for Ctrl+Shift+C */

document.body.addEventListener('keyup', function(evt){
	if (evt.ctrlKey && evt.shiftKey && evt.key == "C"){
		// Throw away this event and don't do the default stuff
		evt.stopPropagation();
		evt.preventDefault();
	}
}, false);