Tip: how to use your MacBook on OS X Lion with the cover open and the display off

Not everyone will find it useful, but for those who did not like this change in behavior from OS X Lion, the solution to reversing it is fortunately quite simple.

If you want to use your MacBook with the lid open but the display is off (when connected to an external monitor, such as an HDTV), open the Terminal and enter the following:

(code lang = ”cpp”) sudo nvram boot-args = "iog = 0x0" (/ code)

Done!

To return to the original state of the Lion, simply reset the PRAM on restarting your machine (by pressing and holding Option + Command + P + R) or by typing the following line in the Terminal:

(code lang = ”cpp”) sudo nvram -d boot-args (/ code)

There are some advantages to using the machine in this way, including battery saving (which means it works much cooler) and better Wi-Fi signal reception.

(tip from Anderson Mancini, via Mac OS X Hints)