Programming Tutorials

bless in Mac OS X

By: Strauss K in macos Tutorials on 2011-02-03  

bless is a command line utility in macOS that sets a disk's boot information. It can also be used to select the startup disk, set the firmware boot device, or change the volume's Universal Unique Identifier (UUID) prefix.

Here are some common uses of the bless command:

  1. Set the startup disk: sudo bless --mount /Volumes/MyDisk --setBoot This command sets the startup disk to the volume mounted at /Volumes/MyDisk.

  2. Set the firmware boot device: sudo bless --device /dev/disk0s2 --setBoot --nextonly This command sets the firmware boot device to the device at /dev/disk0s2, but only for the next boot.

  3. Change the UUID prefix: sudo bless --folder /Volumes/MyDisk/System/Library/CoreServices --uuid <new prefix> This command changes the UUID prefix of the volume's system folder to the specified value.

Note that bless should be used with caution, as incorrect usage can render a system unbootable.

Add Comment

* Required information


No comments yet. Be the first!

Most Viewed Articles (in macos )

Latest Articles (in macos)