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bless(8)                  BSD System Manager's Manual                 bless(8)


NAME

     bless -- set volume bootability and startup disk options


SYNOPSIS

     bless --help

     bless --folder directory [--file file] [--bootinfo [file]]
           [--bootefi [file]] [--label name | --labelfile file] [--setBoot]
           [--openfolder directory] [--nextonly] [--shortform] [--legacy]
           [--legacydrivehint device] [--options string] [--quiet | --verbose]

     bless --mount directory [--file file] [--setBoot] [--nextonly]
           [--shortform] [--legacy] [--legacydrivehint device]
           [--options string] [--quiet | --verbose]

     bless --device device [--label name | --labelfile file]
           [--startupfile file] [--setBoot] [--nextonly] [--shortform]
           [--legacy] [--legacydrivehint device] [--options string]
           [--quiet | --verbose]

     bless --netboot --server url [--nextonly] [--options string]
           [--quiet | --verbose]

     bless --info [directory] [--getBoot] [--plist] [--quiet | --verbose]
           [--version]

     bless --unbless directory


DESCRIPTION

     bless is used to modify the volume bootability characteristics of
     filesystems, as well as select the active boot volume.  bless has 6 modes
     of execution: Folder Mode, Mount Mode, Device Mode, NetBoot Mode, Info
     Mode, and Unbless Mode.

     Folder Mode allows you to select a directory on a mounted volume to act
     as the ``blessed'' directory, which causes the system firmware to look in
     that directory for boot code. EFI-based systems also support a
     ``blessed'' system file, which is the primary mechanism of specifying the
     booter for a volume for those systems. In Folder Mode, if you are operat-
     ing on an HFS+ volume, the HFS+ Volume Header is updated to reflect the
     files/directories given, which persists even if the volume is moved to
     another system or NVRAM is cleared.

     Mount Mode does not make permanent modifications to the filesystem, but
     rather set the system firmware to boot from the specified volume, assum-
     ing it has been properly blessed. This is a subset of the functionality
     of Folder Mode with the --setBoot option, but is convenient when you
     don't want to change or interrogate the filesystem for its blessed sta-
     tus.

     Device Mode is similar to Mount Mode, but allows selection of unmounted
     filesystems, for instance while in single user mode. It can also perform
     certain offline modifications to the filesystem, but is not generally
     recommended.

     NetBoot Mode sets the system firmware to boot from the network, using a
     URL syntax to specify the protocol and server.  bless only sets the local
     system to go into NetBoot mode, and does not communicate to the server
     what image should be used, if there are multiple images. Some other mech-
     anism, such as using Startup Disk, should be used to select that.

     Info Mode will print out the currently-blessed directory of a volume, or
     if no mountpoint is specified, the active boot volume that the firmware
     is set to boot from.

     Unbless Mode complements Folder Mode, and clears the persistent blessed
     folder and file information on HFS+ volumes.

     Additionally, --help can be used to display the command-line usage sum-
     mary.

   FILE/FOLDER MODE
     Folder Mode has the following options:
     --folder directory       Set this directory to be the Mac OS X/Darwin
                              blessed directory, containing a BootX secondary
                              loader for New World machines.
     --file file              Set this file to be the Mac OS X/Darwin blessed
                              boot file, containing a booter for EFI-based
                              systems. If this option is not provided, a
                              default boot file is used based on the blessed
                              directory.
     --bootinfo [file]        Create a BootX file in the Mac OS X/Darwin sys-
                              tem folder using file as a source. If file is
                              not provided, a default is used (see FILES),
                              using a path relative to the mountpoint you are
                              blessing. This attempts to ensure that a BootX
                              is used that is compatible with the OS on the
                              target volume.
     --bootefi [file]         Create a boot.efi file in the Mac OS X/Darwin
                              system folder using file as a source. If file is
                              not provided, a default is used (see FILES),
                              using a path relative to the mountpoint you are
                              blessing. This attempts to ensure that a
                              boot.efi is used that is compatible with the OS
                              on the target volume. If --file is also pro-
                              vided, the new file will be created at that path
                              instead.
     --label name             Render a text label used in the firmware-based
                              OS picker
     --labelfile file         Use a pre-rendered label used for the firmware-
                              based OS picker
     --openfolder directory   Specify a folder to be opened in the Finder when
                              the volume is mounted by the system.
     --setBoot                Set the system to boot off the specified parti-
                              tion. This is implemented in a platform-specific
                              manner. On Open Firmware-based systems, the
                              boot-device variable is modified. On EFI-based
                              systems, the efi-boot-device variable is
                              changed.
     --nextonly               Only change the boot device selection for the
                              next boot. This is only supported on EFI-based
                              systems.
     --shortform              Use an abbreviated device path form. This option
                              can allow for booting from new devices, at the
                              expense of boot time performance. This is only
                              supported on EFI-based systems.
     --legacy                 If --setBoot is given, set the firmware to boot
                              a legacy BIOS-based operating system from the
                              specified disk. The active flag of an MBR-parti-
                              tioned disk is not modified, which can be done
                              with fdisk(8) . This is only supported on EFI-
                              based systems.
     --legacydrivehint device
                              Instruct the firmware to treat the specified
                              whole disk as the primary, master IDE drive.
                              This is only supported on EFI-based systems.
     --options                Set load options associated with the new boot
                              option. This is only supported on EFI-based sys-
                              tems, and in general should be avoided. Instead,
                              use nvram(8) to set "boot-args" , which will
                              work with both Open Firmware- and EFI-based sys-
                              tems.
     --quiet                  Do not print any output
     --verbose                Print verbose output

   MOUNT MODE
     Mount Mode has the following options:
     --mount directory        Use the volume mounted at directory to change
                              the active boot volume, in conjunction with
                              --setBoot . The volume must already be properly
                              blessed.
     --file file              Instead of allowing the firmware to discover the
                              booter based on the blessed directory or file,
                              pass an explicit path to the firmware to boot
                              from. This can be used to run EFI applications
                              or EFI booters for alternate OSes, but should
                              not be normally used. This is only supported on
                              EFI-based systems.
     --setBoot                Same as for Folder Mode.
     --nextonly               Same as for Folder Mode.
     --shortform              Same as for Folder Mode.
     --legacy                 Same as for Folder Mode.
     --legacydrivehint device
                              Same as for Folder Mode.
     --options                Same as for Folder Mode.
     --quiet                  Do not print any output
     --verbose                Print verbose output

   DEVICE MODE
     Device Mode has the following options:
     --device device          Use the block device device to change the active
                              boot volume. No volumes should be mounted from
                              device , and the filesystem should already be
                              properly blessed.
     --label name             Set the firmware-based OS picker label for the
                              unmounted filesystem, using name , which should
                              be in UTF-8 encoding.
     --labelfile file         Use a pre-rendered label used with the firmware-
                              based OS picker.
     --setBoot                Set the system to boot off the specified parti-
                              tion, as with Folder and Mount Modes.
     --startupfile file       Add the file as the HFS+ StartupFile, and update
                              other information on disk as appropriate for the
                              startup file type.
     --nextonly               Same as for Folder Mode.
     --shortform              Same as for Folder Mode.
     --options                Same as for Folder Mode.
     --legacy                 Same as for Folder Mode.
     --legacydrivehint device
                              Same as for Folder Mode.
     --quiet                  Do not print any output
     --verbose                Print verbose output

   NETBOOT MODE
     NetBoot Mode has the following options:
     --netboot                Instead of setting the active boot selection to
                              a disk-based volume, set the system to NetBoot.
     --server protocol://[interface@]server
                              A URL specification of how to boot the system.
                              Currently, the only protocol supported is BSDP
                              ("bsdp"), Apple's Boot Service Discovery Proto-
                              col. The interface is optional, and the server
                              is the IPv4 address of the server in dotted-quad
                              notation. If there is not a specific server
                              you'd like to use, pass "255.255.255.255" to
                              have the firmware broadcast for the first avail-
                              able server. Examples of this notation would be
                              "bsdp://255.255.255.255" and
                              "bsdp://en1@17.203.12.203".
     --nextonly               Same as for Folder Mode.
     --options                Same as for Folder Mode.
     --quiet                  Do not print any output
     --verbose                Print verbose output

   INFO MODE
     Info Mode has the following options:
     --info [directory]       Print out the blessed system folder for the vol-
                              ume mounted at directory . If directory is not
                              specified, print information for the currently
                              selected boot volume (which may not necessarily
                              be `/' .
     --getBoot                Print out the logical boot volume, based on what
                              is currently selected. This option will take
                              into account the fact that the firmware may be
                              pointing to an auxiliary booter partition, and
                              will print out the corresponding root partition
                              for those cases. If the system is configured to
                              NetBoot, a URL matching the format of the
                              --server specification for NetBoot mode will be
                              printed.
     --plist                  Output all information in Property List (.plist)
                              format, suitable for parsing by CoreFoundation.
                              This is most useful when bless is executed from
                              another program and its standard output must be
                              parsed.
     --quiet                  Do not print any output
     --verbose                Print verbose output
     --version                Print bless version and exit immediately

   UNBLESS MODE
     Unbless Mode has the following options:
     --unbless directory      Use the HFS+ volume mounted at directory and
                              unset any persistent blessed files/directories
                              in the HFS+ Volume Header.


FILES

     /usr/standalone/ppc/bootx.bootinfo  Secondary loader with XML headers,
                                         used with the --bootinfo flag. Used
                                         for booting New World PPC-based Mac-
                                         intoshes. If the argument to
                                         --bootinfo is ommitted, this file
                                         will be used as the default input.
     /usr/standalone/i386/boot.efi       Booter for EFI-based systems, used
                                         with the --bootefi flag. If the argu-
                                         ment to --bootefi is ommitted, this
                                         file will be used as the default
                                         input.
     /System/Library/CoreServices        Typical blessed folder for Mac OS X
                                         and Darwin


EXAMPLES

   FOLDER MODE
     To bless a volume with only Mac OS X or Darwin, and create the BootX and
     boot.efi files as needed:

           bless --folder "/Volumes/Mac OS X/System/Library/CoreServices"
           --bootinfo --bootefi

   MOUNT MODE
     To set a volume containing either Mac OS 9 and Mac OS X to be the active
     volume:

           bless --mount "/Volumes/Mac OS" --setBoot

   NETBOOT MODE
     To set the system to NetBoot and broadcast for an available server:

           bless --netboot --server bsdp://255.255.255.255

   INFO MODE
     To gather information about the currently selected volume (as determined
     by the firmware), suitable for piping to a program capable of parsing
     Property Lists:

           bless --info --plist


SEE ALSO

     mount(8), newfs(8), nvram(8)

Mac OS X                         May 24, 2013                         Mac OS X

Mac OS X 10.9 - Generated Thu Oct 17 06:35:22 CDT 2013
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