Xmobar and dzen2 are two poplar status panel for XMonad, because they can be hooked into the logHook and display the status of XMonad. But they are not interactively friendly. Although I can use keyboard to perform all the tasks, in very rare cases, I still want to be able to use only one hand and the mouse.

Fortunately, latest version ¹ of dzen2 supports mouse action on region. But XMonad does not support client command to invoke windows management command. Two tools wmctrl and xdotool can help to resolve this problem. The former can interact with any EWMH/NetWM compatible X Window Manager, and the latter can simulate keyboard input. So my solution is adding mouse action in dzen2, use wmctrl to switch desktop and xdotool to change layout.

Starting from Emacs 23, I start Emacs as a daemon (using emacs --daemon) when starting X session. And use emacsclient to bring up a frame (see my script emacs-dwim). When quitting X session, I send a HUP signal to Emacs.

pidof emacs && killall emacs && sleep 3
emacs --daemon &

ck-launch-session "$MY_WM" &
wait $!

killall -HUP emacs

Recently I find out features like ido, recentf no longer save histories into files so that they cannot restore after restart. These features all add hook in `kill-emacs-hook'. But in the daemon mode, it has no opportunity to run `kill-emacs-hook' because the process is killed by SIGHUP or SIGTERM, where the hooks are not ran in such case.

emacsclient -e -n '
(progn
  (dolist (f (cdr-safe (reverse (frame-list))))
    (delete-frame f t))
  (kill-emacs))
'
declare -i c=1
while pgrep emacs && [ $c -le 3 ] && sleep $c; do
    c=c+1
done
killall -HUP emacs

(add-hook 'server-switch-hook 
          (lambda ()
            (when (current-local-map)
              (use-local-map (copy-keymap (current-local-map))))
            (local-set-key (kbd "C-x k") 'server-edit)))

(setq iy/delete-frame-functions
      '(anything-c-adaptive-save-history
        w3m-cookie-shutdown
        w3m-arrived-shutdown
        recentf-save-list
        ido-kill-emacs-hook))

(defun iy/run-delete-frame-hooks (frame)
  (when (and (server-running-p)
             (= 2 (length (frame-list))))
    (dolist (f iy/delete-frame-functions)
      (when (fboundp f)
        (funcall f)))))

(add-hook 'delete-frame-functions 'iy/run-delete-frame-hooks)

Default diff-mode is really ugly, I prefer using color to indicate changes, green for added and red for removed. Fortunately, we can customized faces in diff-mode ourselves.

Following is my customization:

(custom-set-faces
  ;; custom-set-faces was added by Custom.
  ;; If you edit it by hand, you could mess it up, so be careful.
  ;; Your init file should contain only one such instance.
  ;; If there is more than one, they won't work right.
 '(diff-added ((t (:foreground "#559944"))))
 '(diff-context ((t nil)))
 '(diff-file-header ((((class color) (min-colors 88) (background dark)) (:foreground "RoyalBlue1"))))
 '(diff-function ((t (:foreground "#00bbdd"))))
 '(diff-header ((((class color) (min-colors 88) (background dark)) (:foreground "RoyalBlue1"))))
 '(diff-hunk-header ((t (:foreground "#fbde2d"))))
 '(diff-nonexistent ((t (:inherit diff-file-header :strike-through nil))))
 '(diff-refine-change ((((class color) (min-colors 88) (background dark)) (:background "#182042"))))
 '(diff-removed ((t (:foreground "#de1923")))))

And the sample display:

diff --git a/lisp/org-exp.el b/lisp/org-exp.el
index ed1778c..905a065 100644
--- a/lisp/org-exp.el
+++ b/lisp/org-exp.el
@@ -2109,9 +2109,11 @@ is a string, prepend it to the first line instead of PREFIX."
    (insert (or prefix1 prefix))
    (setq prefix1 nil)
    (beginning-of-line 2)))
-    (buffer-string)
     (goto-char (point-min))
-    (while (re-search-forward "^\\(\\*\\|[ \t]*#\\)" nil t)
+    (while (re-search-forward "^[ \t]*#+\\(TITLE\\|AUTHOR\\|EMAIL\\|DATE\\|DESCRIPTION\\|KEYWORDS\\|LANGUAGE\\|OPTIONS\\|INFOJS_OPT\\|EXPORT_SELECT_TAGS\\|EXPORT_EXCLUDE_TAGS\\|LINK_UP\\|LINK_HOME\\).*$" nil t)
+      (replace-match "" nil nil))
+    (goto-char (point-min))
+    (while (re-search-forward "^\\*" nil t)
       (goto-char (match-beginning 0))
       (insert ",")
       (end-of-line 1))

You can merge these into your face customizations. They are generated by customize-face in the default custom file (~/.emacs).

I use the dark theme Blackboard, in which the background color is "#0C1021" and foreground color is "#F8F8F8" (Sample Text). So the theme may be only readable in dark theme. You can customize-group "diff-mode" to generate your own diff-mode theme.

In Ubuntu, command update-alternatives maintains symbolic links determining default commands. This article introduces how to switch gcc-4.1 and gcc-4.3 as default compiler in Ubuntu.

Install Packages

It seems that both gcc-4.1 and gcc-4.3 are installed after I install build-essential. However, we can explicitly install the following packages:

$ sudo apt-get install gcc-4.1 gcc-4.3 g++-4.1 g++-4.3

Install Alternatives

Symbolic links cc and c++ are installed by default. We will install symbol links for gcc and g++, then link cc and c++ to gcc and g++ respectively.

$ sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-4.1 10
$ sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-4.3 20

$ sudo update-alternatives --install /usr/bin/g++ g++ /usr/bin/g++-4.1 10
$ sudo update-alternatives --install /usr/bin/g++ g++ /usr/bin/g++-4.3 20

$ sudo update-alternatives --install /usr/bin/cc cc /usr/bin/gcc 30
$ sudo update-alternatives --set cc /usr/bin/gcc

$ sudo update-alternatives --install /usr/bin/c++ c++ /usr/bin/g++ 30
$ sudo update-alternatives --set c++ /usr/bin/g++

Configure Alternatives

The last step is configuring the default commands for gcc, g++. It's easy to switch between 4.1 and 4.3 interactively:

$ sudo update-alternatives --config gcc
$ sudo update-alternatives --config g++

Or switch using script:

#!/bin/sh

if [ -z "$1" ]; then
    echo "usage: $0 version" 1>&2
    exit 1
fi

if [ ! -f "/usr/bin/gcc-$1" ] || [ ! -f "/usr/bin/g++-$1" ]; then
    echo "no such version gcc/g++ installed" 1>&2
    exit 1
fi

update-alternatives --set gcc "/usr/bin/gcc-$1"
update-alternatives --set g++ "/usr/bin/g++-$1"