How many clipboards are in system?

Of the three selections, users should only be concerned with PRIMARY and CLIPBOARD. SECONDARY is only used inconsistently and was intended as an alternate to PRIMARY. Different applications may treat PRIMARY and CLIPBOARD differently; however, there is a degree of consensus that CLIPBOARD should be used for Windows-style clipboard operations, while PRIMARY should exist as a “quick” option, where text can be selected using the mouse or keyboard, then pasted using the middle mouse button (or some emulation of it). This can cause confusion and, in some cases, inconsistent or undesirable results from rogue applications.

prevent multi-line paste in bash

I often use ctrl+c to copy text from some gui application and then paste it into my terminal emulator (terminator), using right-mouse-click-menu and paste. Sometimes I forget that the clipboard contains several lines, which when pasted into bash causes each line to be “executed”