For a long time, we used the bless command to startup systems to a specific volume in OS X. Back in 2009 I started using the systemsetup command for more and more tasks. These days, I’m being guided to replace all of my bless options in scripts to systemsetup. The easy way to configure your startup volumes using systemsetup is to list the available volumes, set one as the startup volume and then check to see which one is the current volume. The first task is to list the available startup volumes, using the -liststartupdisks option:
sudo systemsetup -liststartupdisks
You can then set the disk as one that was listed by the above command:
sudo systemsetup -setstartupdisk /Volumes/HAVOKMELTDOWN
You can finally check the current startup disk as a sanity check in your script to verify the desired disk is the startup volume using -getstartupdisk
sudo systemsetup -getstartupdisk
