$get-clipboard-text-hook
special-variable
A user supplied function to return the contents of the clipboard as a string. Called by the paste (CTRL+V) keyboard shortcut in the REPL. The default unix implementation is:
(setq $get-clipboard-text-hook #(shell:exec-with-io-redirect null "xsel" "-o" "-b"))
The program xsel can be installed through the xsel package (Debian).