Automatically change backgrounds in Xfce 4.10

1. download a list of background pictures
2. right click on the desktop, and choose "Desktop Settings..."
3. under "Background" tab, choose "Image list" on the right
4. click "+" to add background pictures to the list
5. choose "Change the background (in minutes)", and adjust the minutes
6. if you have one monitor, choose "Stretched" for "Style"; if you have two monitors, choose "Tiled", and choose "Stretch this background across all monitors"

Install Xfce 4.10 in Xubuntu 12.04

sudo add-apt-repository ppa:xubuntu-dev/xfce-4.10
sudo apt-get udpate
sudo apt-get dist-upgrade

Firefox Tip: Delete One Item From History

It is especially helpful if you type Gogle instead of Google, which makes Gogle recorded in Firefox history.

1. Enter the partial name in the url bar, say "Gog"
2. Select the error url

3. Shift + Delete

How To Run Android 4.0 In Virtualbox (Linux)

http://blog.pengyifan.com/how-to-run-android-4-0-in-virtualbox-linux/

Inkscape doesn't open on ubuntu 12.04

inkscape keeps crashing while loading, and the error message doesn't give any hint.

Emergency save activated!
Emergency save completed. Inkscape will close now.
If you can reproduce this crash, please file a bug at www.inkscape.org
with a detailed description of the steps leading to the crash, so we can fix it.

The problem is that I substituted its icon in .icons. Then a conflict took place... Now, I've just undo that and inkscape return to work.

How to do Research At the MIT AI Lab

English version (html): http://www.cs.indiana.edu/mit.research.how.to.html

English version (pdf): www.cs.umass.edu/~emery/misc/how-to.pdf

Chinese version (pdf): https://www.box.com/s/633b3828e96427de4c9b

Change default file manager (Ubuntu)

exo-preferred-applications