apk fie install from termina

$ echo $PATH ---(should return the directories associated with $PATH)

$ export PATH=$PATH:/home/YOUR-USERNAME/sdk/tools
---(replace with path to your tools directory, you may need to add 'sudo' to the beginning of this cmd)
Update: later versions of the SDK have ADB moved to the platform-tools directory, so adjust the above accordingly.


$ echo $PATH 
---(you should now see your tools directory added to the end of the $PATH variable)

$ adb devices
---(now adb should do something, if nothing else at least error, no devices)


And now I get:

List of devices attached
emulator-5554 device




uninstall cmd:   adb uninstall com.stylingandroid.viewpager

install cmd:  adb install ~/Downloads/BarcodeScanner3.6.apk