adb command debug android

installation and tutorial:
https://www.youtube.com/watch?v=V0MyTvgfO7s

detail from official web:
http://developer.android.com/intl/zh-CN/tools/help/adb.html

adb devices
List of devices attached
emulator-5554  device
emulator-5556  device
emulator-5558  device

adb logcat