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


     tmutil -- Time Machine utility


     tmutil verb [options]


     tmutil provides methods of controlling and interacting with Time Machine,
     as well as examining and manipulating Time Machine backups. Common abili-
     ties include restoring data from backups, editing exclusions, and compar-
     ing backups.

     Several, but not all, verbs require root privileges.


     Throughout this manual, specific language is used to describe particular
     "realms" associated with Time Machine backups. It is important to under-
     stand this terminology to make effective use of tmutil and its manual.

     backup source
             A volume currently being backed up by Time Machine.

     backup disk
             The HFS+ volume that contains Time Machine backups.

     backup destination
             In the case of a local destination, a synonym for backup disk.
             For network destinations, this is the AFP or SMB share on which
             the backup disk image resides.

     backup disk image (or backup image)
             A sparsebundle that, when mounted, is the backing store for a
             volume that is a backup disk.

     backup store
             The top-level "Backups.backupdb" directory at the root of a
             backup disk. E.g.,


     machine directory
             A directory inside a backup store that contains all the backups
             for a particular computer. For local destinations, a backup store
             can contain multiple machine directories, all for separate com-
             puters. E.g.,


             A directory inside a machine directory that represents a single
             initial or incremental backup of one computer. The word "snap-
             shot", in most contexts, is a generic term and is not to be con-
             fused with a "local Time Machine snapshot", which is simply a
             snapshot stored locally on the computer. E.g.,


     snapshot volume
             A directory inside a snapshot that represents a single initial or
             incremental backup of one backup source. E.g.,

             lae/2011-07-03-123456/Mac HD


     Each verb is listed with its description and individual arguments.

     setdestination [-ap] arg
             Configure a local HFS+ volume, AFP share, or SMB share as a
             backup destination. Requires root privileges.

             When the -a option is provided, arg will be added to the list of
             destinations. Time Machine will automatically choose a backup
             destination from the list when performing backups. When the -a
             option is not provided, the current list of destinations will be
             replaced by arg.

             If you wish to set an HFS+ volume as the backup destination, arg
             should be the mount point of the volume in question. When setting
             an AFP or SMB destination arg takes the form:


             In the AFP and SMB cases, the password component of the URL is
             optional; you may instead specify the -p option to enter the
             password at a non-echoing interactive prompt. This is of particu-
             lar interest to the security-conscious, as all arguments provided
             to a program are visible by all users on the system via the ps

     destinationinfo [-X]
             Print information about destinations currently configured for use
             with Time Machine. For each backup destination, the following
             information may be displayed:

                 Name          The volume label as shown in Finder.
                 Kind          Whether the destination is locally attached
                               storage or a network device.
                 URL           In the case of a network destination, the URL
                               used for Time Machine configuration.
                 Mount Point   If the volume is currently mounted, the path in
                               the file system at which it was mounted.
                 ID            The unique identifier for the destination.

             When more than one destination is configured, the most recent
             backup destination will be marked with the > indicator.

             When the -X option is provided, output will be printed in XML
             property list format.

     removedestination identifier
             Remove the destination with the specified unique identifier from
             the Time Machine configuration. Requires root privileges.

             To obtain the unique identifier for a destination, see

     addexclusion [-pv] item ...
             Configure an exclusion that tells Time Machine not to back up a
             file, directory, or volume during future backups.

             There are three kinds of user-configurable exclusions in Time

             The first kind of exclusion, which is the default behavior for
             the addexclusion verb, is a location-independent ("sticky")
             exclusion that follows a file or directory. When the file or
             directory is moved, the exclusion goes with the item to the new
             location. Additionally, when the item is copied, the copy retains
             the exclusion.

             The second kind of exclusion is a fixed-path exclusion. With
             this, you tell Time Machine that you want a specific path to be
             excluded, agnostic of the item at that path. If there is no file
             or directory at the specified path, the exclusion has no effect;
             if the item previously at the path has been moved or renamed, the
             item is not excluded, because it does not currently reside at the
             excluded path. As a consequence of these semantics, moving a file
             or directory to the path will cause the item to be
             excluded--fixed-path exclusions are not automatically cleaned up
             when items are moved or deleted and will take effect again once
             an item exists at an excluded path.

             The third kind of exclusion is a volume exclusion. These track
             volumes based on file system UUID, which is persistent across
             volume name and mount path changes. Erasing the volume will cause
             Time Machine to apply default behavior for the newly erased vol-

             The -p option configures fixed-path exclusions. The -v option
             configures volume exclusions. Both require root privileges.

     removeexclusion [-pv] item ...
             Configure Time Machine to back up a file, directory, or volume
             during future backups. This verb follows the same usage, exclu-
             sion style, and privilege semantics as addexclusion.

     isexcluded [-X] item ...
             Determine if a file, directory, or volume are excluded from Time
             Machine backups.

             When the -X option is provided, output will be printed in XML
             property list format.

             # example output for an excluded item
             thermopylae:~ thoth$ tmutil isexcluded /Users/admin/Desk-
             [Excluded]      /Users/admin/Desktop/foo.txt

             # example output for an item that is not excluded
             thermopylae:~ thoth$ tmutil isexcluded /Users/admin/Desk-
             [Included]      /Users/admin/Desktop/bar.txt

             Turn on automatic backups. Requires root privileges.

             Turn off automatic backups. Requires root privileges.

     startbackup [-a | --auto] [-b | --block] [-r | --rotation] [-d |
             --destination dest_id]
             Begin a backup if one is not already running.

                 --auto           Run the backup in a mode similar to system-
                                  scheduled backups.
                 --block          Wait (block) until the backup is finished
                                  before exiting.
                 --rotation       Allow automatic destination rotation during
                                  the backup.
                 --destination    Perform the backup to the destination corre-
                                  sponding to the specified ID.

             The --auto option provides a supported mechanism with which to
             trigger "automatic-like" backups, similar to automatic backups
             that are scheduled by the system. While this is not identical to
             true system-scheduled backups, it provides custom schedulers the
             ability to achieve some (but not all) behavior normally exhibited
             when operating in automatic mode.

             Cancel a backup currently in progress.

     compare [-@acdefglmnstuEUX] [-D depth] [-I name] [snapshot_path | path1
             Perform a backup diff.

             If no arguments are provided, tmutil will compare the computer to
             the latest snapshot. If a snapshot path is provided as the sole
             argument, tmutil will compare the computer to the specified snap-
             shot. If two path arguments are provided, tmutil will compare
             those two items to each other.  tmutil will attempt to inform you
             when you have asked it to do something that doesn't make sense or
             isn't supported.

             The compare verb allows you to specify what properties to com-
             pare. If you specify no property options, tmutil assumes a
             default property set of -@gmstu. Specifying any property option
             overrides the default set.

                 -a    Compare all supported metadata.
                 -n    No metadata comparison.
                 -@    Compare extended attributes.
                 -c    Compare creation times.
                 -d    Compare file data forks.
                 -e    Compare ACLs.
                 -f    Compare file flags.
                 -g    Compare GIDs.
                 -m    Compare file modes.
                 -s    Compare sizes.
                 -t    Compare modification times.
                 -u    Compare UIDs.
                 -D    Limit traversal depth to depth levels from the begin-
                       ning of iteration.
                 -E    Don't take exclusions into account when comparing items
                       inside volumes.
                 -I    Ignore paths with a path component equal to name during
                       iteration. This may be specified multiple times.
                 -U    Ignore logical volume identity (volume UUIDs) when
                       directly comparing a local volume or snapshot volume to
                       a snapshot volume.
                 -X    Print output in XML property list format.

     verifychecksums path ...
             Compute a checksum of data contained within a backup and verify
             the result(s) against checksum information computed at the time
             of backup.

             No output is generated for matching checksums. Issues are
             reported using the following legend:

                 !    The file's current checksum does not match the expected
                      recorded checksum.
                 ?    The file's recorded checksum is invalid.

             Beginning in OS X 10.11, Time Machine records checksums of files
             copied into snapshots. Checksums are not retroactively computed
             for files that were copied by earlier releases of OS X.

     restore [-v] src ... dst
             Restore the item src, which is inside a snapshot, to the location
             dst. The dst argument mimics the destination path semantics of
             the cp tool. You may provide multiple source paths to restore.
             The last path argument must be a destination.

             When using the restore verb, tmutil behaves largely like Finder.
             Custom Time Machine metadata (extended security and other) will
             be removed from the restored data, and other metadata will be

             Root privileges are not strictly required to perform restores,
             but tmutil does no permissions preflighting to determine your
             ability to restore src or its descendants. Therefore, depending
             on what you're restoring, you may need root privileges to perform
             the restore, and you should know this ahead of time. This is the
             same behavior you would encounter with other copy tools such as
             cp or ditto. When restoring with tmutil as root, ownership of the
             restored items will match the state of the items in the backup.

     delete path ...
             Delete one or more snapshots, machine directories, or backup
             stores. This verb can delete items from backups that were not
             made by, or are not claimed by, the current machine. Requires
             root privileges.

             Print the path to the most recent snapshot for this computer.

             Print paths for all of this computer's completed snapshots.

             Print the path to the current machine directory for this com-

     calculatedrift machine_directory
             Analyze the snapshots in a machine directory and determine the
             amount of change between each. Averages are printed after all
             snapshots have been analyzed. This may require root privileges,
             depending on the contents of the machine directory.

     uniquesize path ...
             Analyze the specified path and determine its unique size. The
             figure reported by uniquesize represents things that only exist
             in the specified path; things that are hard-linked in other
             places are not tallied.

     inheritbackup {machine_directory | sparsebundle}
             Claim a machine directory or sparsebundle for use by the current
             machine. Requires root privileges.

             Machine directories and sparsebundles are owned by one computer
             at a time, and are tracked by unique identifiers rather than com-
             puter name, host name, or ethernet address. The inheritbackup
             verb reassigns the identity of the specified item, reconfiguring
             it so the current host recognizes it during backups. When inher-
             iting a sparsebundle, the machine directory within will also be

             Inheriting is typically only one step in the process of configur-
             ing a backup for use by a machine. You may also need to use
             setdestination, associatedisk, or both, depending on the situa-

             One machine can own multiple machine directories and sparsebun-
             dles, but it is ill-advised for them to reside in the same place.
             In such a situation, which will be chosen during a backup is
             undefined. As a result, inheritbackup will attempt to detect pos-
             sible identity collisions before making changes.

     associatedisk [-a] mount_point snapshot_volume
             Bind a snapshot volume directory to the specified local disk,
             thereby reconfiguring the backup history. Requires root privi-

             In Mac OS X, HFS+ volumes have a persistent UUID that is assigned
             when the file system is created. Time Machine uses this identi-
             fier to make an association between a source volume and a snap-
             shot volume. Erasing the source volume creates a new file system
             on the disk, and the previous UUID is not retained. The new UUID
             causes the source volume -> snapshot volume association to be
             broken. If one were just erasing the volume and starting over, it
             would likely be of no real consequence, and the new UUID would
             not be a concern; when erasing a volume in order to clone another
             volume to it, recreating the association may be desired.

             A concrete example of when and how you would use associatedisk:

             After having problems with a volume, you decide to erase it and
             manually restore its contents from a Time Machine backup or copy
             of another nature. (I.e., not via Time Machine System Restore or
             Migration Assistant.) On your next incremental backup, the data
             will be copied anew, as though none of it had been backed up
             before. Technically, it is true that the data has not been backed
             up, given the new UUID. However, this is probably not what you
             want Time Machine to do. You would then use associatedisk to
             reconfigure the backup so it appears that this volume has been
             backed up previously:

             thermopylae:~ thoth$ sudo tmutil associatedisk [-a] "/Vol-
             umes/MyNewStuffDisk" "/Volumes/Chronoton/Backups.backupdb/ther-

             The result of the above command would associate the snapshot vol-
             ume MyStuff in the specified snapshot with the source volume
             MyNewStuffDisk. The snapshot volume would also be renamed to
             match. The -a option tells associatedisk to find all snapshot
             volumes in the same machine directory that match the identity of
             MyStuff, and then perform the association on all of them.

             Turn on local Time Machine snapshots. Requires root privileges.

             Turn off local Time Machine snapshots and trigger automatic
             cleanup of accumulated local snapshot data. Requires root privi-

             Create new local Time Machine snapshot.


     In most situations, tmutil exits 0 on success, >0 otherwise.

Mac OS X                         10 June 2015                         Mac OS X

Mac OS X 10.12.3 - Generated Thu Feb 9 19:28:46 CST 2017
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