Ctrl+C & and Ctrl+V are not supported in your exam terminal.
To copy and paste text, please use;
6.1 For Linux: select text for copy and middle button for paste (or both left and right simultaneously if you have no middle button).
6.2 For Mac: ⌘+C to copy and ⌘+V to paste.
6.3 For Windows: Ctrl+Insert to copy and Shift+Insert to paste.
6.4 In addition, you might find it helpful to use the Notepad (see top menu under 'Exam Controls') to manipulate text before pasting to the command line.