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HDIUTIL(1)                BSD General Commands Manual               HDIUTIL(1)

     hdiutil -- manipulate disk images (attach, verify, burn, etc)

     hdiutil verb [options]

     hdiutil uses the DiskImages framework to manipulate disk images.  Common verbs include attach, detach,
     verify, create, convert, compact, and burn.

     The rest of the verbs are currently: help, info, checksum, chpass, erasekeys, unflatten, flatten,
     imageinfo, isencrypted, mountvol, unmount, plugins, udifrez, udifderez, internet-enable, resize,
     segment, makehybrid, and pmap.

     Disk images are data containers that emulate disks.  Like disks, they can be partitioned and formatted.
     Many common uses of disk images blur the distinction between the disk image container and its content,
     but this distinction is critical to understanding how disk images work.  The terms "attach" and
     "detach" are used to distinguish the way disk images are connected to and disconnected from a system.
     "Mount" and "unmount" are the parallel filesystems options.

     For example, when you double-click a disk image in the Mac OS X Finder, two separate things happen.
     First, the image is "attached" to the system just like an external drive.  Then, the kernel and Disk
     Arbitration probe the new device for recognized file structures.  If any are discovered that should be
     mounted, the associated volumes will mount and appear on the desktop.

     When using disk images, always consider whether an operation applies to the blocks of the disk image
     container or to the (often file-oriented) content of the image.  For example, hdiutil verify verifies
     that the blocks stored in a read-only disk image have not changed since it was created.  It does not
     check whether the filesystem stored within the image is self-consistent (as diskutil verifyVolume
     would). On the other hand, hdiutil create -srcfolder creates a disk image container, puts a filesystem
     in it, and then copies the specified files to the new filesystem.

     The following option descriptions apply to all verbs:

     -verbose be verbose: produce extra progress output and error diagnostics.  This option can help the
              user decipher why a particular operation failed.  At a minimum, the probing of any specified
              images will be detailed.

     -quiet   close stdout and stderr, leaving only hdiutil's exit status to indicate success or failure.
              No /dev entries or mount points will be printed.  -debug and -verbose disable -quiet.

     -debug   be very verbose.  This option is good if a large amount of progress information is needed.  As
              of Mac OS X 10.6, -debug enables -verbose.

     Many hdiutil verbs understand the following options:

     -plist          provide result output in plist format.  Other programs invoking hdiutil are expected to
                     use -plist rather than try to parse the human-readable output.  The usual output is
                     consistent but generally unstructured.

     -puppetstrings  provide progress output that is easy for another program to parse.  PERCENTAGE outputs
                     can include the value -1 which means hdiutil is performing an operation that will take
                     an indeterminate amount of time to complete.  Any program trying to interpret hdiutil's
                     progress should use -puppetstrings.

     -srcimagekey key=value
                     specify a key/value pair for the disk image recognition system.  (-imagekey is normally
                     a synonym)

     -tgtimagekey key=value
                     specify a key/value pair for any image created.  (-imagekey is only a synonym if there
                     is no input image).

     -encryption [AES-128|AES-256]
                     specify a particular type of encryption or, if not specified, the default encryption
                     algorithm.  As of 10.7, the default algorithm is the AES cipher running in CBC mode on
                     512-byte blocks with a 128-bit key.

     -stdinpass      read a null-terminated passphrase from standard input.  If the standard input is a tty,
                     the passphrase will be read with readpassphrase(3).  Otherwise, the password is read
                     from stdin.  -stdinpass replaces -passphrase which has been deprecated.  -passphrase is
                     insecure because its argument appears in the output of ps(1) where it is visible to
                     other users and processes on the system.  See EXAMPLES.

     -agentpass      force the default behavior of prompting for a passphrase.  Useful with -pubkey to cre-ate create
                     ate an image protected by both a passphrase and a public key.

     -recover keychain_file
                     specify a keychain containing the secret corresponding to the certificate specified
                     with -certificate when the image was created.

     -certificate cert_file
                     specify a secondary access certificate for an encrypted image.  cert_file must be DER-encoded DERencoded
                     encoded certificate data, which can be created by Keychain Access or openssl(1).

     -pubkey PK1,PK2,...,PKn
                     specify a list of public keys, identified by their hexadecimal hashes, to be used to
                     protect the encrypted image being created.

     -cacert cert    specify a certificate authority certificate.  cert can be either a PEM file or a direc-tory directory
                     tory of certificates processed by c_rehash(1).  See also --capath and --cacert in

     -insecurehttp   ignore SSL host validation failures.  Useful for self-signed servers for which the
                     appropriate certificates are unavailable or if access to a server is desired when the
                     server name doesn't match what is in the certificate.

     -shadow [shadowfile]
                     Use a shadow file in conjunction with the data in the primary image file.  This option
                     prevents modification of the original image and allows read-only images to be attached
                     read/write.  When blocks are being read from the image, blocks present in the shadow
                     file override blocks in the base image.  All data written to an attached device will be
                     redirected to the shadow file.  If not specified, shadowfile defaults to image.shadow.
                     If the shadow file does not exist, it is created.  hdiutil verbs taking images as input
                     accept -shadow, -cacert, and -insecurehttp.

     Verbs that create images automatically append the correct extension to any filenames if the extension
     is not already present.  The creation engine also examines the filename extension of the provided file-name filename
     name and changes its behavior accordingly.  For example, a sparse image can be created without specify-ing specifying
     ing -type SPARSEBUNDLE simply by appending the .sparsebundle extension to the provided filename.

     Each verb is listed with its description and individual arguments.  Arguments to the verbs can be
     passed in any order.  A sector is 512 bytes.

     help       display minimal usage information for each verb.  hdiutil verb -help will provide basic
                usage information for that verb.

     attach image [options]
                attach a disk image as a device.  attach will return information about an already-attached
                image as if it had attached it.  If any associated volumes are unmounted (and mounting is
                not suppressed), they will be remounted.  mount is a poorly-named synonym for attach.  See

                By default, the system applies additional mount options to filesystems backed by untrusted
                devices like disk images: options like nosuid and quarantine.  PERMISSIONS VS. OWNERS
                explains the behavior of such filesystems and EXAMPLES shows how to override some of the
                default behavior.

                The output of attach has been stable since OS X 10.0 (though it was called hdid(8) then) and
                is intended to be program-readable.  It consists of the /dev node, a tab, a content hint (if
                applicable), another tab, and a mount point (if any filesystems were mounted).  Because con-tent content
                tent hints are derived from the partition data, GUID Partition Table types may leak through.
                Common GUIDs such as "48465300-0000-11AA-AA11-0030654" are mapped to their human-readable
                counterparts (here "Apple_HFS").

                Common options: -encryption, -stdinpass, -recover, -imagekey, -shadow, -puppetstrings, and

                -readonly          force the resulting device to be read-only
                -readwrite         attempt to override the DiskImages framework's decision to attach a par-ticular particular
                                   ticular image read-only.  For example, -readwrite can be used to modify
                                   the HFS filesystem on a HFS/ISO hybrid CD image.
                -nokernel          attach with a helper process.  This is (again) the default as of Mac OS X
                -kernel            attempt to attach this image without a helper process; fail if unsup-ported. unsupported.
                                   ported.  Only UDRW, UDRO, UDZO, and UDSP images are supported in-kernel.
                                   Encryption and HTTP are supported by the kernel driver.

                -notremovable      prevent this image from being detached.  Only root can use this option.
                                   A reboot is necessary to cleanly detach an image attached with

                -mount required|optional|suppressed
                                   indicate whether filesystems in the image should be mounted or not.  The
                                   default is required (attach will fail if no filesystems mount).
                -nomount           identical to -mount suppressed.
                -mountroot path    mount volumes on subdirectories of path instead of under /Volumes.  path
                                   must exist.  Full mount point paths must be less than MNAMELEN characters
                                   (increased from 90 to 1024 in OS X 10.6).
                -mountrandom path  like -mountroot, but mount point directory names are randomized with
                -mountpoint path   assuming only one volume, mount it at path instead of in /Volumes. See
                                   fstab(5) for ways a system administrator can make particular volumes
                                   automatically mount in particular filesystem locations by editing the
                                   file /etc/fstab.
                -nobrowse          render any volumes invisible in applications such as the OS X Finder.
                -owners on|off     specify that owners on any filesystems be honored or not.
                -drivekey key=value
                                   specify a key/value pair to be set on the device in the IOKit registry.
                -section subspec
                                   Attach a subsection of a disk image.  subspec is any of <offset>, <first-
                                   last>, or <start,count> in 0-based sectors.  Ranges are inclusive.

                The following options have corresponding elements in the
                preferences domain and thus can be rendered in both the positive and the negative to over-ride override
                ride any existing preferences.

                -[no]verify       do [not] verify the image.  By default, hdiutil attach attempts to intel-ligently intelligently
                                  ligently verify images that contain checksums before attaching them.  If
                                  hdiutil can write to an image it has verified, attach will store an
                                  attribute with the image so that it will not be verified again unless its
                                  timestamp changes.  To maintain backwards compatibility, hdid(8) does not
                                  attempt to verify images before attaching them.
                                  Preferences keys: skip-verify, skip-verify-remote, skip-verify-locked,
                                  specify whether bad checksums should be ignored.  The default is to abort
                                  when a bad checksum is detected.
                                  Preferences key: ignore-bad-checksums
                -[no]idme         do [not] perform IDME actions on IDME images.  IDME actions are not per-formed performed
                                  formed by default.
                                  Preferences key: skip-idme
                -[no]idmereveal   do [not] reveal (in the Finder) the results of IDME processing.
                                  Preferences key: skip-idme-reveal
                -[no]idmetrash    do [not] put IDME images in the trash after processing.
                                  Preferences key: skip-idme-trash
                -[no]autoopen     do [not] auto-open volumes (in the Finder) after attaching an image.  By
                                  default, double-clicking a read-only disk image causes the resulting vol-ume volume
                                  ume to be opened in the Finder.  hdiutil defaults to -noautoopen.
                -[no]autoopenro   do [not] auto-open read-only volumes.
                                  Preferences key: auto-open-ro-root
                -[no]autoopenrw   do [not] auto-open read/write volumes.
                                  Preferences key: auto-open-rw-root
                -[no]autofsck     do [not] force automatic file system checking before mounting a disk
                                  image.  By default, only quarantined images (e.g. downloaded from the
                                  Internet) that have not previously passed fsck are checked.
                                  Preferences key: auto-fsck

     detach dev_name [-force]
                detach a disk image and terminate any associated process.  dev_name is a partial /dev node
                path (e.g. "disk1").  As of OS X 10.4, dev_name can also be a mountpoint.  If Disk Arbitra-tion Arbitration
                tion is running, detach will use it to unmount any filesystems and detach the image.  If
                not, detach will attempt to unmount any filesystems and detach the image directly (using the
                `eject' ioctl).  If Disk Arbitration is not running, it may be necessary to unmount the
                filesystems with umount(8) before detaching the image.  eject is a synonym for detach.  In
                common operation, detach is very similar to diskutil(8)'s eject.

                -force   ignore open files on mounted volumes, etc.

     verify image [options]
                compute the checksum of a "read-only" or "compressed" image and verify it against the value
                stored in the image.  Read/write images don't contain checksums and thus can't be verified.
                verify accepts the common options -encryption, -stdinpass, -srcimagekey, -puppetstrings, and

     create size_spec image
                create a new image of the given size or from the provided data.  If image already exists,
                -ov must be specified or create will fail.  To make a cross-platform CD or DVD, use
                makehybrid instead.  See also EXAMPLES below.

                The size specified is the size of the image to be created.  Filesystem and partition layout
                overhead (80 sectors for the default GPTSPUD layout on Intel machines) may not be available
                for the filesystem and user data in the image.
                Size specifiers:
                -size ??b|??k|??m|??g|??t|??p|??e
                           Specify the size of the image in the style of mkfile(8) with the addition of
                           tera-, peta-, and exa-bytes sizes (note that 'b' specifies a number of sectors,
                           not bytes).  The larger sizes are useful for large sparse images.
                -sectors sector_count
                           Specify the size of the image file in 512-byte sectors.
                -megabytes size
                           Specify the size of the image file in megabytes (1024*1024 bytes).

                -srcfolder source
                           copies file-by-file the contents of source into image, creating a fresh (theoret-ically (theoretically
                           ically defragmented) filesystem on the destination.  The resulting image is thus
                           recommended for use with asr(8) since it will have a minimal amount of unused
                           space.  Its size will be that of the source data plus some padding for filesystem
                           overhead.  The filesystem type of the image volume will match that of the source
                           as closely as possible unless overridden with -fs.  Other size specifiers, such
                           as -size, will override the default size calculation based on the source content,
                           allowing for more or less free space in the resulting filesystem.  -srcfolder can
                           be specified more than once, in which case the image volume will be populated at
                           the top level with a copy of each specified filesystem object.  -srcdir is a syn-onym. synonym.
                -srcdevice device
                           specifies that the blocks of device should be used to create a new image.  The
                           image size will match the size of device.  resize can be used to adjust the size
                           of resizable filesystems and writable images.  Both -srcdevice and -srcfolder can
                           run into errors if there are bad blocks on a disk.  One way around this problem
                           is to write over the files in question in the hopes that the drive will remap the
                           bad blocks.  Data will be lost, but the image creation operation will subse-quently subsequently
                           quently succeed.  Filesystem options (like -fs, -volname, -stretch, or -size) are
                           invalid and ignored when using -srcdevice.

                Common options: -encryption, -stdinpass, -certificate, -pubkey, -imagekey, -tgtimagekey,
                -puppetstrings, and -plist.

                -imagekey di-sparse-puma-compatible=TRUE and -imagekey di-shadow-puma-compatible=TRUE will
                create, respectively, sparse and shadow images that can be attached on OS X 10.1.  -imagekey
                encrypted-encoding-version can select between version 1 and version 2 of the encrypted
                encoding.  The framework preferences have a corresponding key to change the default for all
                images.  Version 2 is not compatible with OS X 10.2 but is more robust for SPARSE (UDSP)
                images.  Version 1 is the default for non-sparse images.  As of OS X 10.4.7, sparse
                encrypted images always use version 2 and as of OS X 10.5, all encrypted images default to
                version 2.

                General options:
                -align alignment
                          specifies a size to which the final data partition will be aligned.  The default
                          is 4K.

                -type UDIF|SPARSE|SPARSEBUNDLE
                          -type is particular to create and is used to specify the format of empty
                          read/write images.  It is independent of -format which is used to specify the
                          final read-only image format when populating an image with pre-existing content.

                          UDIF is the default type.  If specified, a UDRW of the specified size will be cre-ated. created.
                          ated.  SPARSE creates a UDSP: a read/write single-file image which expands as is
                          is filled with data.  SPARSEBUNDLE creates a UDSB: a read/write image backed by a
                          directory bundle.

                          By default, UDSP images grow one megabyte at a time.  Introduced in 10.5, UDSB
                          images use 8 MB band files which grow as they are written to.  -imagekey
                          sparse-band-size=size can be used to specify the number of 512-byte sectors that
                          will be added each time the image grows.  Valid values for SPARSEBUNDLE range from
                          2048 to 16777216 sectors (1 MB to 8 GB).

                          The maximum size of a SPARSE image is 128 petabytes; the maximum for SPARSEBUNDLE
                          is just under 8 exabytes (2^63 - 512 bytes minus 1 byte).  The amount of data that
                          can be stored in either type of sparse image is additionally bounded by the
                          filesystem in the image and by any partition map.  compact can reclaim unused
                          bands in sparse images backing HFS+ filesystems.  resize will only change the vir-tual virtual
                          tual size of a sparse image.  See also USING PERSISTENT SPARSE IMAGES below.

                -fs filesystem
                          where filesystem is one of HFS+, HFS+J (JHFS+), HFSX, JHFS+X, MS-DOS, or UDF.  -fs
                          causes a filesystem of the specified type to be written to the image.  -fs may
                          change the partition scheme and type appropriately.  -fs will not make any size
                          adjustments: if the image is the wrong size for the specified filesystem, create
                          will fail.  -fs is invalid and ignored when using -srcdevice.
                -volname volname
                          The newly-created filesystem will be named volname.  The default depends the
                          filesystem being used; HFS+'s default volume name is `untitled'.  -volname is
                          invalid and ignored when using -srcdevice.
                -uid uid  the root of the newly-created volume will be owned by the given numeric user id.
                          99 maps to the magic `unknown' user (see hdid(8)).
                -gid gid  the root of the newly-created volume will be owned by the given numeric group id.
                          99 maps to `unknown'.
                -mode mode the root of the newly-created volume will have mode (in octal) mode.  The default
                          mode is determined by the filesystem's newfs unless -srcfolder is specified, in
                          which case the default mode is derived from the specified filesystem object.
                          do [not] suppress automatically making backwards-compatible stretchable volumes
                          when the volume size crosses the auto-stretch-size threshold (default: 256 MB).
                          See also asr(8).
                -stretch max_stretch
                          -stretch initializes HFS+ filesystem data such that it can later be stretched on
                          older systems (which could only stretch within predefined limits) using hdiutil
                          resize or by asr(8).  max_stretch is specified like -size.  -stretch is invalid
                          and ignored when using -srcdevice.
                -fsargs newfs_args
                          additional arguments to pass to whatever newfs program is implied by -fs.
                          newfs_hfs(8) has a number of options that can reduce the amount of space needed by
                          the filesystem's data structures.  Suppressing the journal with -fs HFS+ and pass-ing passing
                          ing arguments such as -c c=64,a=16,e=16 to -fsargs will minimize gaps at the front
                          of the filesystem, allowing resize to squeeze more space from the filesystem.  For
                          truly optimal filesystems, use makehybrid.

                -layout layout
                          Specify the partition layout of the image.  layout can be anything supported by
                          MediaKit.framework.  NONE creates an image with no partition map.  When such an
                          image is attached, a single /dev entry will be created (e.g. /dev/disk1).

                          `SPUD' causes a DDM and an Apple Partition Scheme partition map with a single
                          entry to be written.  `GPTSPUD' creates a similar image but with a GUID Partition
                          Scheme map instead.  When attached, multiple /dev entries will be created, with
                          either slice 1 (GPT) or slice 2 (APM) as the data partition.  (e.g. /dev/disk1,
                          /dev/disk1s1, /dev/disk1s2).

                          Unless overridden by -fs, the default layout is `GPTSPUD' (PPC systems used `SPUD'
                          prior to OS X 10.6).  Other layouts include `MBRSPUD' and `ISOCD'.  create -help
                          lists all supported layouts.
                -library bundle
                          specify an alternate layout library.  The default is MediaKit's MKDrivers.bundle.
                -partitionType partition_type
                          Change the type of partition in a single-partition disk image.  The default is
                          Apple_HFS unless -fs implies otherwise.

                -ov       overwrite an existing file.  The default is not to overwrite existing files.
                -attach   attach the image after creating it.  If no filesystem is specified via -fs, the
                          attach will fail per the default attach -mount required behavior.

                Image from source options (for -srcfolder and -srcdevice):
                -format format Specify the final image format.  The default when a source is specified is
                               UDZO.  format can be any of the format parameters used by convert.

                Options specific to -srcdevice:
                -segmentSize size_spec
                               Specify that the image should be written in segments no bigger than size_spec
                               (which follows -size conventions).

                Options specific to -srcfolder:
                -[no]crossdev   do [not] cross device boundaries on the source filesystem.
                -[no]scrub      do [not] skip temporary files when imaging a volume.  Scrubbing is the
                                default when the source is the root of a mounted volume.  Scrubbed items
                                include trashes, temporary directories, swap files, etc.
                -[no]anyowners  do not fail if the user invoking hdiutil can't ensure correct file ownership
                                for the files in the image.
                -skipunreadable skip files that can't be read by the copying user and don't authenticate.
                -copyuid user   perform the copy as the given user.  Requires root privilege.  If user can't
                                read or create files with the needed owners, -anyowners or -skipunreadable
                                must be used to prevent the operation from failing.

                By default, create -srcfolder attempts to maintain the permissions present in the source
                directory.  It prompts for authentication if it detects an unreadable file, a file owned by
                someone other than the user creating the image, or a SGID file in a group that the copying
                user is not in.

     convert image -format format -o outfile
                convert image to type format and write the result to outfile.

                As with create, the correct filename extension will be added only if it isn't part of the
                provided name.  Format is one of:

                      UDRW - UDIF read/write image
                      UDRO - UDIF read-only image
                      UDCO - UDIF ADC-compressed image
                      UDZO - UDIF zlib-compressed image
                      UDBZ - UDIF bzip2-compressed image (OS X 10.4+ only)
                      UFBI - UDIF entire image with MD5 checksum
                      UDRo - UDIF read-only (obsolete format)
                      UDCo - UDIF compressed (obsolete format)
                      UDTO - DVD/CD-R master for export
                      UDxx - UDIF stub image
                      UDSP - SPARSE (grows with content)
                      UDSB - SPARSEBUNDLE (grows with content; bundle-backed)
                      RdWr - NDIF read/write image (deprecated)
                      Rdxx - NDIF read-only image (Disk Copy 6.3.3 format)
                      ROCo - NDIF compressed image (deprecated)
                      Rken - NDIF compressed (obsolete format)
                      DC42 - Disk Copy 4.2 image

                In addition to the compression offered by some formats, the UDIF and NDIF read-only formats
                skip unused space in HFS, UFS, and MS-DOS (FAT) filesystems.  For UDZO, -imagekey
                zlib-level=value allows the zlib compression level to be specified ala gzip(1).  The default
                compression level is 1 (fastest).

                Common options: -encryption, -stdinpass, -certificate, -srcimagekey, -tgtimagekey, -shadow
                and related, -puppetstrings, and -plist.

                Other options:
                -align alignment
                             The default is 4 (2K).
                -pmap        add partition map.
                             When converting a NDIF to a any variety of UDIF, or when converting an unparti-tioned unpartitioned
                             tioned UDIF, the default is true.
                -segmentSize [size_spec]
                             Specify segmentation into size_spec-sized segments as outfile is being written.
                             The default size_spec when -segmentSize is specified alone is 2*1024*1024 (1 GB
                             worth of sectors) for UDTO images and 4*1024*1024 (2 GB segments) for all other
                             image types.  size_spec can also be specified ??b|??k|??m|??g|??t??p|??e like
                             create's -size flag.
                -tasks task_count
                             When converting an image into a compressed format, specify the number of
                             threads to use for the compression operation.  The default is the number of
                             processors active in the current system.

     burn image
                Burn image to optical media in an attached burning device.  In all cases, a prompt for media
                will be printed once an appropriate drive has been found.  Common options: -shadow and
                related, -srcimagekey, -encryption, -puppetstrings, and -stdinpass.

                Other options:
                -device          specify a device to use for burning.  See -list.
                -testburn        don't turn on laser (laser defaults to on).
                -anydevice       explicitly allow burning to devices not qualified by Apple (kept for back-wards backwards
                                 wards compatibility as burn will burn to any device by default as of OS X

                -[no]eject       do [not] eject disc after burning. The default is to eject the disc.
                -[no]verifyburn  do [not] verify disc contents after burn.  The default is to verify.

                -[no]addpmap     do [not] add partition map if necessary.  Some filesystem types will not be
                                 recognized when stored on optical media unless they are enclosed in a par-tition partition
                                 tition map.  This option will add a partition map to any bare filesystem
                                 which needs a partition map in order to be recognized when burned to opti-cal optical
                                 cal media.  The default is to add the partition map if needed.

                -[no]skipfinalfree do [not] skip final free partition.  If there is a partition map on the
                                 image specifying an Apple_Free partition as the last partition, that
                                 Apple_Free partition will not be burned.  The burned partition map will
                                 still reference the empty space.  The default is to skip burning a final
                                 free partition.

                -[no]optimizeimage do [not] optimize filesystem for burning.  Optimization can reduce the
                                 size of an HFS or HFS+ volume to the size of the data contained on the vol-ume. volume.
                                 ume.  This option will change what is burned such that the disc will have a
                                 different checksum than the image it came from.  The default is to burn all
                                 blocks of the disk image (minus any trailing Apple_Free).

                -[no]forceclose  do [not] force the disc to be closed after burning.  Further burns to the
                                 disc will be impossible.  The default is not to close the disc.

                -nounderrun      Disable the default buffer underrun protection.

                -[no]synthesize  [Don't] Synthesize a hybrid filesystem for the disc.  The default is to
                                 create a new (HFS/ISO) filesystem when the source image's blocks could not
                                 be legally burned to a disc.

                -speed x_factor  1, 2, 4, 6, ...  `max'
                                 The desired "x-factor".  e.g. 8 means the drive will be instructed burn at
                                 "8x speed".  `max' will cause the burn to proceed at the maximum speed of
                                 the drive.  `max' is the default speed.  Slower speeds can produce more
                                 reliable burns.  The speed factor is relative to the media being burned
                                 (e.g.  -speed 2 has a different data rate when used for a DVD burn vs. a CD
                                 burn).  Note that some drives have a minimum burn speed in which case any
                                 slower speed specified will result in a burn at the drive's minimum speed.

                -sizequery       calculate the size of disc required (the size returned is in sectors) with-out without
                                 out burning anything.

                -erase           prompt for optical media (DVD-RW/CD-RW) and then, if the hardware supports
                                 it, quickly erase the media.  If an image is specified, it will be burned
                                 to the media after the media has been erased.
                -fullerase       erase all sectors of the disc (this usually takes quit a bit longer than
                -list            list all burning devices, with OpenFirmware paths suitable for -device.

     makehybrid -o image source
                Generate a potentially-hybrid filesystem in a read-only disk image using the DiscRecording
                framework's content creation system.  This disk image will represent a data disc.  drutil(1)
                can be used to make audio discs.

                source can either be a directory or a disk image.  The generated image can later be burned
                using burn, or converted to another read-only format with convert.  By default, the filesys-tem filesystem
                tem will be readable on most modern computing platforms.  The generated filesystem is not
                intended for conversion to read/write, but can safely have its files copied to a read/write
                filesystem by ditto(8) or asr(8) (in file-copy mode).

                hdiutil supports generating El Torito-style bootable ISO9660 filesystems, which are commonly
                used for booting x86-based hardware. The specification includes several emulation modes. By
                default, an El Torito boot image emulates either a 1.2MB, 1.44MB, or 2.88MB floppy drive,
                depending on the size of the image.  Also available are "No Emulation" and "Hard Disk
                Emulation" modes, which allow the boot image to either be loaded directly into memory, or be
                virtualized as a partitioned hard disk, respectively. The El Torito options should not be
                used for data CDs.

                Filesystem options:
                -hfs    Generate an HFS+ filesystem.  This filesystem can be present on an image simultane-ously simultaneously
                        ously with an ISO9660 or Joliet or UDF filesystem.  On operating systems that under-stand understand
                        stand HFS+ as well as ISO9660 and UDF, like Mac OS 9 or Mac OS X, it is usually the
                        preferred filesystem.
                -iso    Generate an ISO9660 Level 2 filesystem with Rock Ridge extensions.  This filesystem
                        can be present on an image simultaneously with an HFS+ or Joliet or UDF filesystem.
                        ISO9660 is the standard cross-platform interchange format for CDs and some DVDs, and
                        is understood by virtually all operating systems.  If an ISO9660 or Joliet filesys-tem filesystem
                        tem is present on a disk image or CD, but not HFS+, Mac OS X will use the ISO9660
                        (or Joliet) filesystem.
                -joliet Generate Joliet extensions to ISO9660.  This view of the filesystem can be present
                        on an image simultaneously with HFS+, and requires the presence of an ISO9660
                        filesystem.  Joliet supports Unicode filenames, but is only supported on some oper-ating operating
                        ating systems.  If both an ISO9660 and Joliet filesystem are present on a disk image
                        or CD, but not HFS+, Mac OS X will prefer the Joliet filesystem.
                -udf    Generate a UDF filesystem. This filesystem can be present on an image simultaneously
                        with HFS+, ISO9660, and Joliet. UDF is the standard interchange format for DVDs,
                        although operating system support varies based on OS version and UDF version.

                By default, if no filesystem is specified, the image will be created with all four filesys-tems filesystems
                tems as a hybrid image.  When multiple filesystems are selected, the data area of the image
                is shared between all filesystems, and only directory information and volume meta-data are
                unique to each filesystem.  This means that creating a cross-platform ISO9660/HFS+ hybrid
                has a minimal overhead when compared to a single filesystem image.

                Other options (most take a single argument):
                -hfs-blessed-directory Path to directory which should be "blessed" for Mac OS X booting on
                                       the generated filesystem.  This assumes the directory has been other-wise otherwise
                                       wise prepared, for example with bless -bootinfo to create a valid
                                       BootX file.  (HFS+ only).
                -hfs-openfolder        Path to a directory that will be opened by the Finder automatically.
                                       See also the -openfolder option in bless(8) (HFS+ only).
                -hfs-startupfile-size  Allocate an empty HFS+ Startup File of the specified size, in bytes
                                       (HFS+ only).

                -abstract-file         Path to a file in the source directory (and thus the root of the gen-erated generated
                                       erated filesystem) for use as the ISO9660/Joliet Abstract file
                -bibliography-file     Path to a file in the source directory (and thus the root of the gen-erated generated
                                       erated filesystem) for use as the ISO9660/Joliet Bibliography file
                -copyright-file        Path to a file in the source directory (and thus the root of the gen-erated generated
                                       erated filesystem) for use as the ISO9660/Joliet Copyright file
                -application           Application string (ISO9660/Joliet).
                -preparer              Preparer string (ISO9660/Joliet).
                -publisher             Publisher string (ISO9660/Joliet).
                -system-id             System Identification string (ISO9660/Joliet).
                -keep-mac-specific     Expose Macintosh-specific files (such as .DS_Store) in non-HFS+
                                       filesystems (ISO9660/Joliet).
                -eltorito-boot         Path to an El Torito boot image within the source directory. By
                                       default, floppy drive emulation is used, so the image must be one of
                                       1200KB, 1440KB, or 2880KB. If the image has a different size, either
                                       -no-emul-boot or -hard-disk-boot must be used to enable "No
                                       Emulation" or "Hard Disk Emulation" mode, respectively
                -hard-disk-boot        Use El Torito Hard Disk Emulation mode. The image must represent a
                                       virtual device with an MBR partition map and a single partition
                -no-emul-boot          Use El Torito No Emulation mode. The system firmware will load the
                                       number of sectors specified by -boot-load-size and execute it, with-out without
                                       out emulating any devices (ISO9660/Joliet).
                -no-boot               Mark the El Torito image as non-bootable. The system firmware may
                                       still create a virtual device backed by this data. This option is not
                                       recommended (ISO9660/Joliet).
                -boot-load-seg         For a No Emulation boot image, load the data at the specified segment
                                       address.  This options is not recommended, so that the system
                                       firmware can use its default address (ISO9660/Joliet)
                -boot-load-size        For a No Emulation boot image, load the specified number of 512-byte
                                       emulated sectors into memory and execute it. By default, 4 sectors
                                       (2KB) will be loaded (ISO9660/Joliet).
                -eltorito-platform     Use the specified numeric platform ID in the El Torito Boot Catalog
                                       Validation Entry or Section Header. Defaults to 0 to identify x86
                                       hardware (ISO/Joliet).
                -eltorito-specification For complex layouts involving multiple boot images, a plist-format-ted plist-formatted
                                       ted string can be provided, using either OpenStep-style syntax or XML
                                       syntax, representing an array of dictionaries. Any of the El Torito
                                       options can be set in the sub-dictionaries and will apply to that
                                       boot image only. If -eltorito-specification is provided in addition
                                       to the normal El Torito command-line options, the specification will
                                       be used to populate secondary non-default boot entries.
                -udf-version           Version of UDF filesystem to generate. This can be either "1.02" or
                                       "1.50".  If not specified, it defaults to "1.50" (UDF).

                -default-volume-name   Default volume name for all filesystems, unless overridden.  If not
                                       specified, defaults to the last path component of source.
                -hfs-volume-name       Volume name for just the HFS+ filesystem if it should be different
                                       (HFS+ only).
                -iso-volume-name       Volume name for just the ISO9660 filesystem if it should be different
                                       (ISO9660 only).
                -joliet-volume-name    Volume name for just the Joliet filesystem if it should be different
                                       (Joliet only).
                -udf-volume-name       Volume name for just the UDF filesystem if it should be different
                                       (UDF only).

                -hide-all              A glob expression of files and directories that should not be exposed
                                       in the generated filesystems.  The string may need to be quoted to
                                       avoid shell expansion, and will be passed to glob(3) for evaluation.
                                       Although this option cannot be used multiple times, an arbitrarily
                                       complex glob expression can be used.
                -hide-hfs              A glob expression of files and directories that should not be exposed
                                       via the HFS+ filesystem, although the data may still be present for
                                       use by other filesystems (HFS+ only).
                -hide-iso              A glob expression of files and directories that should not be exposed
                                       via the ISO filesystem, although the data may still be present for
                                       use by other filesystems (ISO9660 only).  Per above, the Joliet hier-archy hierarchy
                                       archy will supersede the ISO hierarchy when the hybrid is mounted as
                                       an ISO 9660 filesystem on Mac OS X.  Therefore, if Joliet is being
                                       generated (the default) -hide-joliet will also be needed to hide the
                                       file from mount_cd9660(8).
                -hide-joliet           A glob expression of files and directories that should not be exposed
                                       via the Joliet filesystem, although the data may still be present for
                                       use by other filesystems (Joliet only).  Because OS X's ISO 9660
                                       filesystem uses the Joliet catalog if it is available, -hide-joliet
                                       effectively supersedes -hide-iso when the resulting filesystem is
                                       mounted as ISO on OS X.
                -hide-udf              A glob expression of files and directories that should not be exposed
                                       via the UDF filesystem, although the data may still be present for
                                       use by other filesystems (UDF only).
                -only-udf              A glob expression of objects that should only be exposed in UDF.
                -only-iso              A glob expression of objects that should only be exposed in ISO.
                -only-joliet           A glob expression of objects that should only be exposed in Joliet.

                -print-size            Preflight the data and calculate an upper bound on the size of the
                                       image.  The actual size of the generated image is guaranteed to be
                                       less than or equal to this estimate.
                -plistin               Instead of using command-line parameters, use a standard plist from
                                       standard input to specific the parameters of the hybrid image genera-tion. generation.
                                       tion.  Each command-line option should be a key in the dictionary,
                                       without the leading "-", and the value should be a string for path
                                       and string arguments, a number for number arguments, and a boolean
                                       for toggle options.  The source argument should use a key of "source"
                                       and the image should use a key of "output".

                If a disk image was specified for source, the image will be attached and paths will be eval-uated evaluated
                uated relative to the mountpoint of the image.  No absolute paths can be used in this case.
                If source is a directory, all argument paths should point to files or directories either via
                an absolute path, or via a relative path to the current working directory.

                The volume name options, just like files in the filesystems, may need to be mapped onto the
                legal character set for a given filesystem or otherwise changed to obey naming restrictions.
                Use drutil(1) as drutil filename myname to see how a given string would be remapped.

                The -abstract-file, -bibliography-file, -and -copyright-file must exist directly in the
                source directory, not a sub-directory, and must have an 8.3 name for compatibility with
                ISO9660 Level 1.

     compact image
                scans the bands of a sparse (SPARSE or SPARSEBUNDLE) disk image containing an HFS filesys-tem, filesystem,
                tem, removing those parts of the image which are no longer being used by the filesystem.
                Depending on the location of files in the hosted filesystem, compact may or may not shrink
                the image.  For SPARSEBUNDLE images, completely unused band files are simply removed.

                Common options: -encryption, -stdinpass, -srcimagekey, -shadow and related, -puppetstrings,
                and -plist.

     info       display information about DiskImages.framework, the disk image driver, and any images that
                are currently attached.  hdiutil info accepts -plist.

     checksum image -type type
                Calculate the specified checksum on the image data, regardless of image type.

                Common options: -shadow and related, -encryption, -stdinpass, -srcimagekey, -puppetstrings,
                and -plist.

                type is one of:
                      UDIF-CRC32 - CRC-32 image checksum
                      UDIF-MD5 - MD5 image checksum
                      DC42 - Disk Copy 4.2
                      CRC28 - CRC-32 (NDIF)
                      CRC32 - CRC-32
                      MD5 - MD5
                      SHA - SHA
                      SHA1 - SHA-1
                      SHA256 - SHA-256
                      SHA384 - SHA-384
                      SHA512 - SHA-512

     chpass image
                change the passphrase for an encrypted image.  The default is to change the password inter-actively. interactively.

                Common options: -recover and -srcimagekey.  The options -oldstdinpass and -newstdinpass
                allow, in the order specified, the null-terminated old and new passwords to be read from the
                standard input in the same manner as with -stdinpass.

     erasekeys image
                securely overwrite keys used to access an encrypted image, quickly rendering the image com-pletely completely
                pletely inaccessible.  Once erasekeys has been run on an encrypted image, there is no feasi-ble feasible
                ble way to recover data from the image file.

                Common options: -plist and -quiet.

     unflatten image
                unflatten a UDIF disk image, creating an OS 9-style dual-fork image file (no XML metadata).
                If the resource fork representation of the metadata becomes greater than 16 MB, the opera-tion operation
                tion will fail with error -39 ("End of fork").

                Common options: -encryption, -stdinpass, and -srcimagekey.

     flatten image
                Flatten a read-only (or compressed) UDIF disk image into a single-fork file.  By default,
                metadata will be stored both as XML (for the kernel's use) and in an embedded resource fork
                (for OS X 10.1 and earlier).

                Common options: -srcimagekey, -encryption, and -stdinpass.  Since images are created "flat"
                by default, flatten is only required if the UDIF has previously been unflattened.

                Other options:
                -noxml      don't embed XML data for in-kernel attachment.  The image will never attach in-kernel. inkernel.
                -norsrcfork don't embed resource fork data.  The image will not attach on OS X versions
                            prior to OS X 10.2.

     fsid image
                Print information about file systems on a given disk image.  Per DEVICE SPECIAL FILES, image
                can be a /dev entry corresponding to a disk.  More detailed information is presented for HFS
                file systems.

                Common options: -encryption, -stdinpass, -srcimagekey, and -shadow and related.

     mountvol dev_name
                mount the filesystem in dev_name using Disk Arbitration (similar to diskutil(8)'s mount).
                XML output is available from -plist.  Note that mountvol (rather than mount, though it often
                works in OS X 10.5 and later) is the correct way to remount a volume after it has been
                unmounted by unmount.

                Prior to OS X 10.5, mount/attach would treat a /dev entry as a disk image to be attached
                (creating another /dev entry).  That behavior was undesirable.

     unmount volume [-force]
                unmount a mounted volume without detaching any associated image.  Volume is a /dev entry or
                mountpoint.  NOTE: unmount does NOT detach any disk image associated with the volume.
                Images are attached and detached; volumes are mounted and unmounted.  hdiutil mountvol (or
                diskutil mount) will remount a volume that has been unmounted by hdiutil unmount.

                -force   unmount filesystem regardless of open files on that filesystem.  Similar to umount

     imageinfo image
                Print out information about a disk image.

                Common options: -encryption, -stdinpass, -srcimagekey, -shadow and related, and -plist.

                Options are any of:
                -format   just print out the image format
                -checksum just print out the image checksum

     isencrypted image
                print a line indicating whether image is encrypted.  If it is, additional details are

                Common options: -plist.

     plugins    print information about DiskImages framework plugins.  The user, system, local, and network
                domains are searched for plugins (i.e.  ~/Library/Plug-ins/DiskImages,
                /System/Library/Plug-ins/DiskImages, /Library/Plug-ins/DiskImages,

                Common options: -plist.

     internet-enable [-yes] | -no | -query image
                Enable or disable download post-processing (IDME).  -yes is the default.  When enabled, a
                browser (or Disk Copy 10.2.3+) will "unpack" the contents: the image's visible contents will
                be copied into the directory containing the image and the image will be put into the trash
                with IDME disabled.

                Common options: -encryption, -stdinpass, -srcimagekey, and -plist.

     resize size_spec image
                Resize a disk image or the containers within it.  For an image containing a trailing
                Apple_HFS partition, the default is to resize the image container, the partition, and the
                filesystem within it by aligning the end of the hosted structures with the end of the image.
                hdiutil resize cannot resize filesystems other than HFS+ and its variants.

                resize can shrink an image so that its HFS/HFS+ partition can be converted to CD-R/DVD-R
                format and still be burned.  hdiutil resize will not reclaim gaps because it does not move
                data.  diskutil(8)'s resize can move filesystem data which can help hdiutil resize create a
                minimally-sized image.  -fsargs can also be used to minimize filesystem gaps inside an

                resize is limited by the disk image container format (e.g. UDSP vs. UDSB), any partition
                scheme, the hosted filesystem, and the filesystem hosting the image.  In the case of HFS+
                inside of GPT inside of a UDRW on HFS+ with adequate free space, the limit is approximately
                2^63 bytes.  Older images created with an APM partition scheme are limited by it to 2TB.
                Before OS X 10.4, resize was limited by how the filesystem was created (see hdiutil create

                hdiutil burn does not burn Apple_Free partitions at the end of the devices, so an image with
                a resized filesystem can be burned to create a CD-R/DVD-R master that contains only the
                actual data in the hosted filesystem (assuming minimal data fragmentation).

                Common options: -encryption, -stdinpass, -srcimagekey, -shadow and related, and -plist.

                Size specifiers:
                -size ??b|??k|??m|??g|??t??p|??e
                -sectors sector_count | min
                                 Specify the number of 512-byte sectors to which the partition should be
                                 resized.  If this falls outside the mininum valid value or space remaining
                                 on the underlying file system, an error will be returned and the partition
                                 will not be resized.  min automatically determines the smallest possible

                Other options:
                -imageonly       only resize the image file, not the partition(s) and filesystems inside of
                -partitiononly   only resize a partition / filesystem in the image, not the image.
                                 -partitiononly will fail if the new size won't fit inside the image.  On
                                 APM, shrinking a partition results in an explicit Apple_Free entry taking
                                 up the remaining space in the image.
                -partitionNumber partitionNumber
                                 specifies which partition to resize (UDIF only -- see HISTORY below).
                                 partitionNumber is 0-based, but, per hdiutil pmap, partition 0 is the par-tition partition
                                 tition map itself.

                -growonly        only allow the image to grow
                -shrinkonly      only allow the image to shrink
                -nofinalgap      allow resize to entirely eliminate the trailing free partition in an APM
                                 map.  Restoring such images to very old hardware may interfere with boot-ing. booting.

                -limits          Displays the minimum, current, and maximum sizes (in 512-byte sectors) for
                                 the image.  In addition to any hosted filesystem constraints, UDRW images
                                 are constrained by available disk space in the filesystem hosting the
                                 image.  -limits does not modify the image.

                segment -o firstSegname -segmentCount #segs image [opts]
                segment -o firstSegname -segmentSize size image [opts]
                segment a NDIF or UDIF disk image.  Segmented images work around limitations in file size
                which are sometimes imposed by filesystems, network protocols, or media.  Note: whether or
                not the segments are encrypted is determined by the options passed to segment and not by the
                state of the source image.

                Common options: -encryption, -stdinpass, -srcimagekey, -tgtimagekey, -puppetstrings, and

                -segmentCount segment_count
                             Specify the number of segments.  Only one of -segmentCount or -segmentSize will
                             be honored.
                -segmentSize segment_size
                             Specify the segment size in sectors or in the style of mkfile(8) (here unquali-fied unqualified
                             fied numbers are still sectors).  If the original image size is not an exact
                             multiple of the segment size, the last segment will be shorter than the others.
                             Only one of -segmentCount or -segmentSize will be honored.  Segmenting
                             read/write (UDRW) images is not supported (as of OS X 10.3).

                -firstSegmentSize segment_size
                             Specify the first segment size in sectors in the same form as for -segmentSize.
                             Used for multi-CD restores.
                -restricted  Make restricted segments for use in multi-CD restores.
                -ov          overwrite any existing files.

     pmap [options] image
                display the partition map of an image or device.  By default, this report includes starting
                offsets and significant amounts of free space.  image is either a disk image or /dev/disk
                entry (see DEVICE SPECIAL FILES).

                Common options: -encryption, -stdinpass, -srcimagekey, and -shadow and related.

                -simple       generate MediaKit's minimal report: basic partition types, names, and sizes in
                              human-readable units.
                -standard     generate MediaKit's standard report, which adds partition offsets and uses
                              512-byte sectors.
                -complete     generate MediaKit's comprehensive report, with end offsets, significant free
                              space, etc.

                -endoffsets   indicate last block of each partition.
                -nofreespace  suppress all free space reporting.  Not valid with -shims.
                -shims        report free space < 32 sectors.
                -uuids        show per-instance UUIDs for each partition.  APM does not store instance UUIDs
                              so these will be randomly generated for APM maps.

     udifrez [options] image
                embed resources (e.g. a software license agreement) in a disk image.

                You must specify one of the following options:
                -xml file
                     Copy resources from the XML in file.
                -rsrcfork file
                     Copy resources from file's resource fork.
                     Delete all pre-existing resources in image.

     udifderez [options] image
                extract resources from image.

                -xml    emit XML output (default)
                -rez    emit Rez format output

                Common options: -encryption, -stdinpass, and -srcimagekey.

           hdiutil verify myimage.img
                 verifies an image against its internal checksum.

           hdiutil segment -segmentSize 10m -o /tmp/aseg 30m.dmg
                 creates aseg.dmg, aseg.002.dmgpart, and aseg.003.dmgpart

           hdiutil convert master.dmg -format UDTO -o master
                 converts master.dmg to a CD-R export image named master.cdr
           hdiutil convert /dev/disk1 -format UDRW -o devimage
                 converts the disk /dev/disk1 to a read/write device image file.  authopen(1) will be used
                 if read access to /dev/rdisk1 is not available.  Note use of the block-special device.

           hdiutil burn myImage.dmg
                 burns the image to optical media and verifies the burn.
           hdiutil burn myRawImage.cdr -noverifyburn -noeject
                 burns the image without verifying the burn or ejecting the disc.  Volumes will be mounted
                 after burning.

     Creating a 50 MB encrypted image:
           hdiutil create -encryption -size 50m e.dmg -fs HFS+J

     Creating a 50 MB encrypted image protected with public key only:
           hdiutil create -encryption -size 50m e.dmg -fs HFS+J \
               -pubkey F534A3B0C2AEE3B988308CC89AA04ABE7FDB5F30

     Creating a 50 MB encrypted image protected with public key and password:
           hdiutil create -encryption -size 50m e.dmg -fs HFS+J -agentpass \
               -pubkey F534A3B0C2AEE3B988308CC89AA04ABE7FDB5F30

     Note that these two -pubkey usage examples assume a certificate corresponding to this public key is
     currently in the user's keychain or smart card.  For additional information on smart card authorization
     setup see sc_auth(8).

     Creating an encrypted single-partition image without user interaction:
           printf pp|hdiutil create -encryption -stdinpass -size 9m sp.dmg

     Creating a "1 GB" SPARSE image (a 1 GB filesystem in a growable file):
           hdiutil create -type SPARSE -size 1g -fs HFS+ growableTo1g

     Creating a "1 GB" SPARSEBUNDLE (a 1 GB filesystem in a growable bundle):
           hdiutil create -type SPARSEBUNDLE -size 1g -fs HFS+ growableTo1g

     Creating a new mounted volume backed by an image:
           hdiutil create -volname Dick -size 1.3m -fs HFS+ -attach Moby.dmg

     Attaching an image on a web server to the system, with any writes going to a local file:
           hdiutil attach -shadow /tmp/mastershadowfile

     Using a shadow file to attach a read-only image read-write to modify it, then convert it back to a
     read-only image. This method eliminates the time/space required to convert a image to read-write before
     modifying it.

           hdiutil attach -owners on Moby.dmg -shadow
           /dev/disk2   Apple_partition_scheme
           /dev/disk2s1 Apple_partition_map
           /dev/disk2s2 Apple_HFS               /Volumes/Moby

           ditto /Applications/ /Volumes/Moby
           hdiutil detach /dev/disk2
           hdiutil convert -format UDZO Moby.dmg -shadow

     Creating a RAM-backed device and filesystem.

           NUMSECTORS=128000       # a sector is 512 bytes
           mydev=`hdiutil attach -nomount ram://$NUMSECTORS`
           newfs_hfs $mydev
           mkdir /tmp/mymount
           mount -t hfs $mydev /tmp/mymount

     Using makehybrid to create cross-platform data with files overlapping between filesystem views.  With
     these files:
           albumlist.txt song2.wma     song4.m4a     song6.mp3     song8.mp3
           song1.wma     song3.m4a     song5.mp3     song7.mp3

           hdiutil makehybrid -o MusicBackup.iso Music -hfs -iso -joliet \
               -hide-hfs 'Music/*.wma' -hide-joliet 'Music/{*.m4a,*.mp3}' \
               -hide-iso 'Music/*.{wma,m4a}'

     will create an image with three filesystems pointing to the same blocks.  The HFS+ filesystem, typi-
     cally only visible on Macintosh systems, will not include the .wma files, but will show the .m4a and
     .mp3 files. The Joliet filesystem will not show the .m4a and .mp3 files, but will show the .wma files.
     The ISO9660 filesystem, typically the default filesystem for optical media on many platforms, will only
     show the .mp3 files. All three filesystems will include the "albumlist.txt" files.

     Image from directory (new-style):
           hdiutil create -srcfolder mydir mydir.dmg

     Image from directory (10.1-style; of historical interest):
           du -s myFolder             # du(1) will count resource forks
           hdiutil create -sectors 10642 folder     # add ~1% for filesytem
           hdid -nomount folder.dmg
           /dev/disk1s2            Apple_HFS
           newfs_hfs -v myFolderImage /dev/rdisk1s2
           hdiutil detach disk1
           hdid folder.dmg
           /dev/disk1s2            Apple_HFS         /Volumes/myFolderImage
           sudo mount -u -t hfs -o perm /dev/disk1s2 /Volumes/myFolderImage
           # optionally enable owners; sudo unneeded if manually mounted

           ditto -rsrcFork myFolder /Volumes/myFolderImage
           hdiutil detach disk1s2          # all done
           hdiutil convert -format UDZO -o folder.z.dmg folder.dmg # compress

     Manually changing ownership settings of a read-only disk image:
           hdiutil attach myimage.dmg
           /dev/disk1s2            Apple_HFS         /Volumes/myVolume
           diskutil unmount disk1s2
           mkdir /Volumes/myVolume
           sudo mount -r -t hfs -o owners /dev/disk1s2 /Volumes/myVolume
           # -o owners is the default for manual mounts

     Forcing a known image to attach:
           hdiutil attach -imagekey diskimage-class=CRawDiskImage

     The following environment variables affect hdiutil and DiskImages:

                enable -verbose behavior for attach.

                enable -debug behavior for attach.

                similar to -nokernel but works even with, for example, create -attach.

                attempt to attach in-kernel first (like attach -kernel). In OS X 10.4.x, in-kernel was the
                default behavior for UDRW and SPARSE images.  On OS X 10.5, these and other kernel-compati-ble kernel-compatible
                ble images, including RAM-based images described in hdid(8), will attach with a user process
                unless attach -kernel is used or the corresponding variable is set.  If an image is not
                "kernel-compatible" and -kernel is specified, the attach will fail.  (WARNING: ram:// images
                currently use wired memory when attached in-kernel).

                disable SSL peer verification the same way -insecurehttp does.  Useful for clients of
                DiskImages such as asr(8) which don't support a similar command line option.

     DiskImages uses many frameworks and can encounter many error codes.  In general, it tries to turn these
     error numbers into localized strings for the user.  For background, intro(2) is a good explanation of
     our primary error domain: the BSD errno values.  For debugging, -verbose should generally provide
     enough information to figure out what has gone wrong.  The following is a list of interesting errors
     that hdiutil may encounter:

     No mountable filesystems
                        The "No mountable filesystems" error from hdiutil attach means that no filesystems
                        could be recognized or mounted after the disk image was attached.  The default
                        behavior in this case is to detach the disk image.  See attach for options modifying
                        this behavior.  This error can occur if the disk image or contained filesystem is
                        corrupt.  It can also occur if an image was created from a block device containing a
                        mounted, journaled filesystem (in which case the image contains a dirty journal that
                        can't be replayed without making the image read/write, such as with attach -shadow).

     [ENXIO]            Device not configured.  This error is returned explicitly by DiskImages when its
                        kernel driver or framework helper cannot be contacted.  It also often shows up when
                        a device has been removed while I/O is still active.  One common case of the helper
                        not being found is when Foundation's Distributed Objects RPC mechanism cannot be
                        configured.  D.O. doesn't work under dead Mach bootstrap contexts such as can exist
                        in a reattached screen(1) session.  Root users can take advantage of
                        StartupItemContext(8) (in /usr/libexec) to access the startup item Mach bootstrap

     [EINVAL]           Invalid argument.  This error is used in many contexts and is often a clue that
                        hdiutil's arguments are subtly non-sensical (e.g. an invalid layout name passed to
                        create -layout).

     [EFBIG]            File too large.  DiskImages reports this error when attempting to access a disk
                        image over HTTP that is too large for the server to support access via Range
                        requests.  Segmented images can sometimes be used to work around this limitation of
                        older HTTP servers.  This error can also occur if an overflow occurs with an old-style oldstyle
                        style UDIF resource fork.

     [EAUTH]            Authentication error.  Used by DiskImages when libcurl(3) is unable to verify its
                        SSL peer or when Security.framework indicates that the user failed to enter the cor-rect correct
                        rect password.  See -insecurehttp and -cacert for more information about verifica-tion verification
                        tion of SSL peers.

     [EBUSY]            Resource busy.  Used if necessary exclusive access cannot be obtained.  This error
                        often appears when a volume can't be unmounted.

     [EAGAIN]           Resource temporarily unavailable.  As of OS X 10.5, DiskImages uses read/write locks
                        on its image files to prevent images from being attached on more than one machine at
                        a time (e.g. over the network).  EAGAIN is returned if the appropriate read or write
                        lock can't be obtained.

     EACCES vs. EPERM   EACCES and EPERM are subtly different.  The latter "operation not permitted" tends
                        to refer to an operation that cannot be performed, often due to an incorrect effec-tive effective
                        tive user ID.  On the other hand, "permission denied" tends to mean that a particu-lar particular
                        lar file access mode prevented the operation.

     As of OS X 10.5, a more reliable, efficient, and scalable sparse format, UDSB (SPARSEBUNDLE), is recom-mended recommended
     mended for persistent sparse images as long as a backing bundle (directory) is acceptable.  OS X 10.5
     also introduced F_FULLFSYNC over AFP (on client and server), allowing proper journal flushes for HFS+J-bearing HFS+Jbearing
     bearing images.  Critical data should never be stored in sparse disk images on file servers that don't
     support F_FULLFSYNC.

     SPARSE (UDSP) images and shadow files were designed for intermediate use when creating other images
     (e.g. UDZO) when final image sizes are unknown.  As of OS X 10.3.2, partially-updated SPARSE images are
     properly handled and are thus safe for persistent storage.  SPARSE images are not recommended for per-sistent persistent
     sistent storage on versions of OS X earlier than 10.3.2 and should be avoided in favor of SPARSEBUNDLE
     images or UDRW images and resize.

     If more space is needed than is referenced by the hosted filesystem, hdiutil resize or diskutil(8)
     resize can help to grow or shrink the filesystem in an image.  compact reclaims unused space in sparse
     images.  Though they request that hosted HFS+ filesystems use a special "front first" allocation pol-icy, policy,
     icy, beware that sparse images can enhance the effects of any fragmentation in the hosted filesystem.

     To prevent errors when a filesystem inside of a sparse image has more free space than the volume hold-ing holding
     ing the sparse image, HFS volumes inside sparse images will report an amount of free space slightly
     less than the amount of free space on the volume on which image resides.  The image filesystem cur-rently currently
     rently only behaves this way as a result of a direct attach action and will not behave this way if, for
     example, the filesystem is unmounted and remounted.

     Since any /dev entry can be treated as a raw disk image, it is worth noting which devices can be
     accessed when and how.  /dev/rdisk nodes are character-special devices, but are "raw" in the BSD sense
     and force block-aligned I/O.  They are closer to the physical disk than the buffer cache.  /dev/disk
     nodes, on the other hand, are buffered block-special devices and are used primarily by the kernel's
     filesystem code.

     It is not possible to read from a /dev/disk node while a filesystem is mounted from it, but anyone with
     read access to the appropriate /dev/rdisk node can use hdiutil verbs such as fsid or pmap with it.
     Beware that information read from a raw device while a filesystem is mounted may not be consistent
     because the consistent data is stored in memory or in the filesystem's journal.

     The DiskImages framework will attempt to use authopen(1) to open any device which it can't open (due to
     EACCES) for reading with open(2).  Depending on session characteristics, this behavior can cause appar-ent apparent
     ent hangs while trying to access /dev entries while logged in remotely (an authorization panel is wait-ing waiting
     ing on console).

     Generally, the /dev/disk node is preferred for imaging devices (e.g.  convert or create -srcdevice
     operations), while /dev/rdisk is usable for the quick pmap or fsid.  In particular, converting the
     blocks of a mounted journaled filesystem to a read-only image will prevent the volume in the image from
     mounting (the journal will be permanently dirty).

     Some filesystems support permissions including users and groups.  While important for security on a
     managed filesystem, users and groups ("owners") pose challenges for unmanaged, shared filesystems such
     as those typically present in disk images.  OS X's solution to this problem is to make owners optional,
     both while creating files and enforcing permissions.

     By default, unknown HFS filesystems on "external" devices (including disk images) mount with their own-ers owners
     ers ignored (mount -o noowners).  When owners are ignored, the system dynamically substitutes the cur-rent current
     rent user's identify for any owners recorded in the filesystem.  When creating new files, a special UID
     and GID of _unknown are recorded on the disk.  Even if a filesystem is later mounted with on-disk own-ers owners
     ers honored, files with stored UID or GID of _unknown will continue to substitute the current user's
     credentials any time the given file is accessed.  The net result is that shared volumes behave as
     expected even when connected to systems where their on-disk owners are honored.

     On modern OS X systems, root (UID 0) can "see through" the _unknown user mappings.  Thus
           sudo ls -l /Volumes/imageVol
     will show whatever is really stored in the filesystem (possibly _unknown) regardless of whether owners
     are currently being respected on that volume.  In contrast, non-root users will see themselves any time
     owners are ignored (either via mount -o noowners or stored _unknown): mary running ls -l will see that
     mary owns any owners-ignored filesystems objects while joe running ls -l on the same objects will see
     that joe owns them.

     Unlike owners, permissions are never optional.  A non-writable file will not be writable just because
     owners are ignored.  However, a file that is writable by its owner will be writable by everyone if own-ers owners
     ers are ignored for that file.  Because anyone accessing an owners-ignored file is treated as the
     owner, everyone is effectively the owner.

     diskutil(8)'s enableOwnership or the Finder's Get Info window can be used to configure a system to
     respect the on-disk owners for a filesystem in the future.

     The DiskImages framework supports a variety of flat-file and dual-fork image formats, including
     read/write, read-only, and read-only compressed (which are decompressed in small chunks as I/O requests
     are made).  It automatically decodes AppleSingle and MacBinary file formats and is capable of mounting
     most images directly from http:// URLs.  Because DiskImages can make many requests over a single con-nection, connection,
     nection, responsiveness can be improved by modifying HTTP server settings such as apache's MaxKeepAliv-eRequests MaxKeepAliveRequests
     eRequests and KeepAliveTimeout.

     OS X 10.0 supported the disk images of Disk Copy 6 on Mac OS 9.  OS X 10.1 added sparse, encrypted, and
     zlib-compressed images.  These images will not be recognized on OS X 10.0 (or will attach read/write,
     possibly allowing for their destruction).  As the sparse, shadow, and encrypted formats have evolved,
     switches have been added to facilitate the creation of images that are compatible with older OS ver-sions versions
     sions (at the expense of the performance and reliability improvements offered by the format enhance-ments). enhancements).
     ments).  In particular, sparse images should not be expected to attach on versions of OS X older than
     that which created them.

     With OS X 10.2, the most common image formats went "in-kernel" (i.e. the DiskImages kernel extension
     served them without a helper process), image meta-data began being stored both as XML and in the embed-ded embedded
     ded resource fork, and the default Disk "compressed" format became UDZO (breaking compatibil-ity compatibility
     ity with 10.0).  OS X 10.4 introduced bzip2 compression in the UDBZ format which provides smaller
     images (especially when combined with makehybrid) at the expense of backwards compatibility.

     In OS X 10.4.7, the resource forks previously embedded in UDIF images were abandoned entirely to avoid
     metadata length limitations imposed by resource fork structures.  As a result, UDIF images created on
     10.4.7 and later will not, by default, be recognized by either OS X 10.1 or OS X 10.0.  flatten can be
     used to customize the type of metadata stored in the image.

     OS X 10.5 introduced sparse bundle images which compact quickly but are not recognized by previous OS
     versions.  OS X 10.6 removed support for attaching SPARSEBUNDLE images from network file servers that
     don't support F_FULLFSYNC. OS X 10.7 removed double-click support for images using legacy metadata;
     these can be rehabilitated using flatten and unflatten, or simply convert.

     Disk images were first invented to electronically store and transmit representations of floppy disks
     for manufacturing replication.  These images of floppies are typically referred to as 'Disk Copy 4.2'
     images, in reference to the application that created and restored them to floppy disks.  Disk Copy 4.2
     images were block-for-block representations of a floppy disk, with no notion of compression.  DART is a
     variant of the Disk Copy 4.2 format that supported compression.

     NDIF (New Disk Image Format) images were developed to replace the Disk Copy 4.2 and DART image formats
     and to support images larger than a floppy disk.  With NDIF and Disk Copy version 6, images could be
     "attached" as mass storage devices under Mac OS 9.  Apple Data Compression (ADC) -- which carefully
     optimizes for fast decompression -- was used to compress images that were typically created once and
     restored many times during manufacturing.

     UDIF (Universal Disk Image Format) device images picked up where NDIF left off, allowing images to rep-resent represent
     resent entire block devices and all the data therein: DDM, partition map, disk-based drivers, etc.  For
     example, it can represent bootable CDs which can then be replicated from an image.  To ensure single-fork singlefork
     fork files (NDIF was dual-fork), it began embedding its resource fork in the data fork.  UDIF is the
     native image format for OS X.

     Raw disk images from other operating systems (e.g. .iso files) will be recognized as disk images and
     can be attached and mounted if OS X recognizes the filesystems.  They can also be burned with hdiutil

     OS X 10.7 added the ability to quickly render encrypted images inaccessible using the new erasekeys
     verb, which saves time versus securely overwriting the entire image.

     In OS X 10.6, pmap was rewritten to use MediaKit's latest reporting routines so that it can properly
     support GPT partition maps.  Also -debug now implies -verbose for all verbs.

     OS X 10.5 changed the behavior of attach when run on an existing image or /dev node: if the image was
     attached but no volume was mounted, the volume would be mounted.  Prior systems would return the /dev
     without mounting the volume.  This change effectively removes the ability to create a second /dev node
     from an existing one.

     authopen(1), diskutil(8), ditto(8), ioreg(8), drutil(1), msdos.util(8), hfs.util(8),
     diskarbitrationd(8), /System/Library/CoreServices/

OS X                              16 Aug 2013                             OS X

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