softwareupdate
Apple has provided a command line utility to match the Aqua software update. This can be scripted to run and also can be run remotely using ssh.
I ran the softwareupdate command by typing in softwareupdate -i -r for install required. The discovery of this command line command is really rather nifty. Next time you need to update your software, you may want to try it. It does give you interactive feedback, so you know what is taking place. After it is finished it will prompt you to restart if that is necessary.