Sub.jam

1. Important directories related to menu and applications
/usr/share/applications/
/etc/xdg/
~/.local
~/.config

2. If icons are missing for some applications in the menu, go to
System->Gnome Control Center ->Main Menu. Find the item and right
click to access the properties. In property setting, you can specify
the icons. There are several ways to locate the icon for application,
say foo. Go to /usr/share/applications/foo.desktop to find the name of
the icon. Then search for the icon, for example, "locate foo.png".

3. You many find out that even some application is removed from the
system, you can still see them in the menu editor (although not in
the menu). Go to ~/.local/share/applications/ and ~/.local/share/applications/kde
to delete the corresponding desktop file.

4. Use CTRL+ALT+F1...F6 switch to raw console;
CTRL+ALT+F7 switch back to GUI

5. Top 10 Gnome Desktop Tweaks

6. ALT 1, 2, ...: switch between different gnome-terminal tabs

7. Gnome-terminal full-screen mode

gnome-terminal --full-screen --hide-menubar