Why does Neo hit Ctrl+X?

When Trinity hacks into his computer and delivers her message, Neo hits CTRL+X. Why?

On Windows hitting CTRL+X will cut (I’m not sure about other operating systems).

A little searching around lead to a forum that suggested a few possibilities:

• It was a way to exit DOS applications
• The OS Neo uses was custom made by him or MetaCortex, so CTRL+X might have a different meaning.

Is their any official explanation?