How to select the current line inside ubuntu terminal with hotkeys and copy it inside main clipboard

How can i select the whole line in ubuntu terminal only with hotkeys?

CTRL+U works, but puts it inside a buffer. How can i copy that buffer into the main clipboard?

Or how can i select/highlight the whole line and copy it with CTRL + SHIFT + C.

The only way i know at the moment is with mouse cursor, right click and copy. But i want to do it without mouse and add it into the main clipboard.

Thank you in advance.