launch genymotion simulator from command line

Command to launch genymotion headless -

player --vm-name Nexus_4

if player is not already added to path, add it to path using below command in your ~/.bash_profile

export PATH=/Applications/Genymotion.app/Contents/MacOS/:$PATH

When more than one device is connect use 'adb -s' is used to redirect commands to particular device
Once emulator is running they will be listed under adb devices
Example:

adb devices
List of devices attached
192.168.56.101:5555 device


Verfiy command are send to correct device:
Send command to click on menu key on android device when multiple devices are connected

adb -s 192.168.56.101:5555 shell input keyevent KEYCODE_MENU