How to copy text from Emacs to another application on Linux

Question

When I cut (kill) text in Emacs 22.1.1 (in its own window on X, in KDE, on Kubuntu), I can\'t paste (yank) it in any other application.

Answer 1

The code below, inspired by @RussellStewart's answer above, adds support for x-PRIMARY and x-SECONDARY, replaces region-active-p with use-region-p to cover the case of an empty region, does not return silently if xsel has not been installed (returns an error message), and includes a "cut" function (emacs C-y, windows C-x).

(defun my-copy-to-xclipboard(arg)
  (interactive "P")
  (cond
    ((not (use-region-p))
      (message "Nothing to yank to X-clipboard"))
    ((and (not (display-graphic-p))
         (/= 0 (shell-command-on-region
                 (region-beginning) (region-end) "xsel -i -b")))
      (error "Is program `xsel' installed?"))
    (t
      (when (display-graphic-p)
        (call-interactively 'clipboard-kill-ring-save))
      (message "Yanked region to X-clipboard")
      (when arg
        (kill-region  (region-beginning) (region-end)))
      (deactivate-mark))))

(defun my-cut-to-xclipboard()
  (interactive)
  (my-copy-to-xclipboard t))

(defun my-paste-from-xclipboard()
  "Uses shell command `xsel -o' to paste from x-clipboard. With
one prefix arg, pastes from X-PRIMARY, and with two prefix args,
pastes from X-SECONDARY."
  (interactive)
  (if (display-graphic-p)
    (clipboard-yank)
   (let*
     ((opt (prefix-numeric-value current-prefix-arg))
      (opt (cond
       ((=  1 opt) "b")
       ((=  4 opt) "p")
       ((= 16 opt) "s"))))
    (insert (shell-command-to-string (concat "xsel -o -" opt))))))

(global-set-key (kbd "C-c C-w") 'my-cut-to-xclipboard)
(global-set-key (kbd "C-c M-w") 'my-copy-to-xclipboard)
(global-set-key (kbd "C-c C-y") 'my-paste-from-xclipboard)