managing virtualbox on the command line
You might want to manage virtualbox (the PC emulator) on the command line. The use case would be if you want to make a virtual machine (VM) on your machine which does not appear on-screen or which is started automatically.
Suppose the virtual machine instance is called 'ubu'. The following commands will be useful. They are self-explanatory. The command VBoxManage should be in /Applications/VirtualBox/Contents/Resources/MacOS/ or similar.
VBoxManage startvm "ubu" --type headless
VBoxManage controlvm "ubu" pause --type headless
VBoxManage controlvm "ubu" resume --type headless
VBoxManage controlvm "ubu" savestate
VBoxManage controlvm "ubu" poweroff --type headless
VBoxManage startvm "ubu" --type gui