How do I access the X11 primary selection (middle-click buffer) separately from the clipboard in Vim on Linux?

Explanation

On X11 Linux systems, there are two independent clipboard-like buffers: the primary selection ("*) and the clipboard ("+). The distinction matters when copying between Vim and other applications. Vim exposes each as a separate register, so you can explicitly read from or write to either one.

How it works

• "* — primary selection: automatically set whenever you highlight text with the mouse in any X11 application, and pasted by middle-clicking. You don't have to press Ctrl+C — just selecting text is enough.
• "+ — clipboard: populated by explicit copy actions (Ctrl+C in most apps). Pasted with Ctrl+V or Shift+Insert.

Both registers support the standard Vim yank, delete, and put operators:

"*y{motion}   " yank to primary selection
"*p           " paste from primary selection
"+y{motion}   " yank to clipboard
"+p           " paste from clipboard

Example

To grab text that another application has highlighted (primary selection) without requiring that app to do a Ctrl+C:

"*p

To copy a Vim visual selection so another app's Ctrl+V will receive it:

V"*y

Tips

• On macOS and Windows, "* and "+ are aliases for the same system clipboard — the distinction only matters on X11
• Check if Vim was compiled with X11 clipboard support: :echo has('x11') (returns 1 if available)
• :set clipboard=unnamed makes "* the default register for all yank and paste operations
• :set clipboard=unnamedplus does the same for "+
• Neovim requires xclip, xsel, or a similar provider to be installed for these registers to work