Android input keyevent with adb shell

Reference list of AOSP supported keycode) 

http://developer.android.com/reference/android/view/KeyEvent.html

0. connect Android Phone with USB to Host PC

 -.  Linked G2 to Ubuntu system.

1. check device

chlrbgh0@Mulder:~$ adb devices

List of devices attached 

06e3f6e9e0243238 device

2. Send keyevent with KEYCODE value to devices

chlrbgh0@Mulder:~$ adb shell input keyevent POWER

" or "

chlrbgh0@Mulder:~$ adb shell

shell@g2$ input keyevent POWER

 -. below are possible too!.

chlrbgh0@Mulder:~$ adb shell input keyevent 26

2. Send sendevent with KEYCODE value to devices

chlrbgh0@Mulder:~$ adb shell sendevent /dev/input/event2 1 102 1

" or "

chlrbgh0@Mulder:~$ adb shell

shell@g2$ sendevent /dev/input/event2 1 102 1

Quite Simple!. :-)