HDIUTIL
NAME
hdiutil -- manipulate disk images SYNOPSIS
hdiutil verb [options] DESCRIPTION
hdiutil uses the DiskImages framework to manipulate disk images. Common verbs include attach, detach, verify, create, convert, and burn. The rest of the verbs are: help, info, load, checksum, chpass, eject (historical synonym for detach), flatten, unflatten, imageinfo, mount (historical synonym for attach), mountvol, unmount, plugins, internet-enable, resize, segment, compact, makehybrid, and pmap. COMMON OPTIONS
All hdiutil verbs accept the following options: -verbose be verbose; default is less output. 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 minimize output in most cases. -debug and -verbose negate almost all of -quiet's functionality. -debug be very verbose. This option is good if a large amount of information about what hdiutil and the DiskImages framework are doing is needed. -debug and -verbose generate almost entirely independent outputs. 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 usual output. The usual output will remain consistent but unstructured. -puppetstrings provide progress output that is easy for another program to parse. 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 [crypto_method] specify a particular type of encryption or, if not specified, the default CEncryptedEncoding. CEncryptedEncoding utilizes the AES cipher 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). -stdinpass replaces -passphrase though the latter is still supported for compatibility. Beware that the password will contain any newlines before the NULL. See the EXAMPLES section. -recover keychain_file specify a keychain containing the secret corresponding to the certificate specified with -certificate when the image was created). The correct alternate secret will unlock the image. -certificate certificate_file specify a secondary access certificate for the image being created. -cacert cert specify a certificate authority certificate. cert can be either a PEM file or a directory of certificates processed by c_rehash(1). See also --capath and --cacert in curl(1). -insecurehttp ignore SSL host validation failures. Useful for selfsigned 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 image. 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 the attached device will be redirected to the shadow file. If not specified, -shadow defaults to image.shadow. If the shadow file does not exist, it is created. Verbs accepting -shadow also accept -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 filename and changes its behavior accordingly. For example, a sparse image can be created without specifying -type SPARSE simply by appending the .sparseimage extension to the provided filename. VERBS
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 full usage information for that verb. attach image [options] attach a disk image to the system as a device. attach, like hdid(8), will return information about an already-attached image as if it had attached it. mount is a synonym for attach. Beware that an image freshly created and attached is treated as a new removable device. See hdid(8) and the EXAMPLES section below for more details. Common options: -encryption, -stdinpass, -recover, -imagekey, -shadow, -puppetstrings, and -plist. Options: -readonly force the resulting device to be read-only -readwrite attempt to override the DiskImages framework's decision to attach a particular 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. -kernel attempt to attach this image without a helper process; fail if not possible. -notremovable prevent this image from being detached. Only root can use this option. -mount required|optional|suppressed indicate whether filesystems in the image should be mounted or not. OS X 10.2.x and earlier defaulted to optional behavior; the default is now required. -nomount identical to -mount suppressed. -mountroot path mount volumes in path instead of in /Volumes. path must exist. -mountrandom path like -mountroot, but mountpoint names are randomized with mkdtemp(3). -mountpoint path assuming only one volume, mount it at path instead of in /Volumes. Note that mountpoint names cannot be greater than MNAMELEN characters (90 as of this writing). See fstab(5) for ways to make particular volumes automatically mount in particular filesystem locations. -union perform a union mount -private suppress mount notifications to the rest of the system. Note that -private can confuse programs using the Carbon File Manager and should generally be avoided. -nobrowse mark the volumes non-browsable in applications such as the Finder. -owners on|off enable or disable owners for HFS+ volumes, potentially overriding the system's default value for the volume. -drivekey key=value specify a key/value pair to be attached to the device in the IOKit registry. The following options have corresponding elements in the com.apple.frameworks.diskimages preferences domain and thus can be rendered in both the positive and the negative: -[no]verify do [not] suppress verification of the image. By default, hdiutil attach verifies all images containing checksums before attaching them. To maintain backwards compatibility, hdid(8) does not attempt to verify images before attaching them. -[no]ignorebadchecksums specify whether bad checksums should be ignored. The default is to abort when a bad checksum is detected. -[no]idme do [not] perform IDME actions on IDME images. IDME actions are normally only performed when a browser downloads and attaches an image. -[no]idmereveal do [not] reveal (in the Finder) the results of IDME processing. -[no]idmetrash do [not] put IDME images in the trash after processing. -[no]autoopen do [not] auto-open volumes (in the Finder) after attaching an image. By default, readonly volumes are auto-opened in the Finder. -[no]autoopenro do [not] auto-open read-only volumes. -[no]autoopenrw do [not] auto-open read/write volumes. detach dev_name [-force] detach a disk image and terminate any associated hdid process. dev_name is a partial /dev node path (e.g. "disk1"). As of OS X 10.4, dev_name can also be a mount point. If Disk Arbitration 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. Options: -force Similar to umount -f. Unmounts any filesystems and detaches the image, regardless of any open files on the image. verify image [options] compute the checksum of a read-only (or compressed) image, and verify it against the value stored in the image. verify accepts the common options -encryption, -stdinpass, -srcimagekey, -puppetstrings, and -plist. 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. If image is attached, it must be detached before it can be overwritten, even if -ov is specified. To make a cross-platform CD or DVD, use makehybrid. See also EXAMPLES below. The size specified is the size of the image to be created. Filesystem and partition layout overhead (64 sectors for the default SPUD layout) will be deducted before space is made for user data in any volume on the image. Size specifiers: -size ??b|??k|??m|??g|??t??p|??e -size specifies 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 when creating large sparse images (up to the SPARSE size limit). -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 directory specifies the image size based on the contents of directory. -srcfolder also causes the contents of directory to be copied to the resulting image. 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 size of the source directory, allowing for extra free space to be left in the filesystem. -srcfolder copies file by file, creating a fresh (theoretically optimized) filesystem on the destination image (which then would be ready to be restored by asr(8)). -srcdir is a synonym for -srcfolder. -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 a filesystem in such an image. 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 when it notices them. Data will be lost, but the image creation operation will subsequently succeed. Common options: -encryption, -stdinpass, -plist, -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 images. Version 1 is the default. General options: -align alignment specifies a size to which the final data partition will be aligned. The default is 4K. -type UDIF|SPARSE UDIF is the default disk image type. If specified, a UDRW of the specified size will be created. Specifying SPARSE creates a UDSP: a read/write image which expands as is is filled with data. The default is to grow one megabyte at a time, but the key sparse-band-size can be used (with -imagekey) to specify the number of sectors that will be added each time the image grows. The maximum size of a SPARSE image is bounded by the filesystem in the image, the partition map (if any), and an internal limit of 128 petabytes. compact can reclaim unused bands in a UDSP if it has an HFS+ filesystem on it. Keep in mind that resize can also resize a UDRW and any HFS filesystem inside. See USING PERSISTENT SPARSE IMAGES below for more information. -fs filesystem where filesystem is one of HFS+, HFS+J, HFSX, HFS, MS-DOS, or UFS. -fs will cause a filesystem of the specified type to be written to the image. -fs may also change the default layout if that particular filesystem is not native to an Apple_HFS partition in an Apple Partition Map. -volname volname The newly-created filesystem will be named volname. The default name is `untitled'. -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. -nouuid suppress adding a UUID to the volume. Such a volume will behave more like a volume which was formatted with OS 9 or earlier. -[no]autostretch do [not] suppress automatically making 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 using hdiutil resize or by asr(8) on older systems (which could only stretch within predefined limits). max_stretch is specified like -size. -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 passing 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, makehybrid should be used. -layout layout Specify the partition layout of the image. layout can be anything specified in MediaKit.framework's MKDrivers.bundle. 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 is an acronym for Single Partition UDIF. SPUD creates an image with a DDM and an Apple Partition Scheme partition map with a single entry for an Apple_HFS partition. When attached, multiple /dev entries will be created and the 2nd partition will be the data partition (e.g. /dev/disk1, /dev/disk1s1, /dev/disk1s2; the second partition is disk1s2). Unless changed by -fs, the default is SPUD. Other layouts include "UNIVERSAL HD" and "UNIVERSAL CD" which add appropriate OS 9 driver partitions for those types of media. OS 9 drivers are not used by OS X nor by its Classic environment. -partitionType partition_type Change the type of partition in a SPUD. The default is Apple_HFS. The principal alternative is Apple_UFS, though the appropriate partition type will be automatically chosen depending on the argument to -fs. -ov overwrite an existing file. The default is not to overwrite existing files. See the note with create about not being allowed to overwrite attached images. -attach attach the image after creating it (plain attach -- use hdiutil attach for more options). Note that 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. -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 with -srcfolder. Scrubbing is the default when the source is the root of a mounted volume. Scrubbed items include trashes, temporary directories, swap, etc. -[no]anyowners do [not] require that the user invoking hdiutil own all of the files in the source. -copyuid user perform the copy as the given user. Normally, the copy is performed to maintain fidelity as explained below. -skipunreadable skip files that can't be read by the copying user and don't authenticate. 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 mentioned above, 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) 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 completely remove unused space in HFS and UFS 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). Options are any of: Common options: -encryption, -stdinpass, -certificate, -srcimagekey, -tgtimagekey, -shadow with friends, -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 unpartitioned 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 with friends, -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 backwards compatibility as burn will burn to any device by default as of OS X 10.4). -[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 partition 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 optical 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 volume. 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) without 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 -erase). -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. 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 filesystem 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 is 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 simultaneously with an ISO9660 or Joliet or UDF filesystem. On operating systems that understand 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 filesystem 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 operating 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 filesystems 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 otherwise 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 generated filesystem) for use as the ISO9660/Joliet Abstract file (ISO9660/Joliet). -bibliography-file Path to a file in the source directory (and thus the root of the generated filesystem) for use as the ISO9660/Joliet Bibliography file (ISO9660/Joliet). -copyright-file Path to a file in the source directory (and thus the root of the generated filesystem) for use as the ISO9660/Joliet Copyright file (ISO9660/Joliet). -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. 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 (ISO9660/Joliet). -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, without emulating any devices (ISO9660/Joliet). -no-boot Mark the El Torito image as nonbootable. 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-formatted string can be provided, using either OpenStepstyle 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 nondefault 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 hierarchy 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 generation. 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 evaluated 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 type disk image with an HFS filesystem in it, removing those parts of the image which are no longer being used by the filesystem. Depending on the organization of files in the filesystem, compact may or may not shrink the image file. Common options: -encryption, -stdinpass, -srcimagekey, -shadow with friends, -puppetstrings, and -plist. info display information about DiskImages.framework, the disk image driver, and any images that are currently attached. hdiutil info accepts -plist. load manually load the disk image driver. Normally, the disk image driver is loaded by the DiskImages framework whenever needed. As of OS X 10.2, the driver will automatically unregister itself after the last image is detached (it will then be unloaded after about a minute without being used again). checksum image -type type Calculate the specified checksum on the image data, regardless of image type. Common options: -shadow with friends, -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 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. unflatten image unflatten a read-only (or compressed) UDIF disk image, creating a dual-fork file in traditional format (resource-only; no XML). Common options: -encryption, -stdinpass, and -srcimagekey. flatten image Flatten a read-only (or compressed) UDIF disk image into a single-fork file. If the image is UDZO or UDBZ format and does not contain XML meta-data for in-kernel attachment, it will be added. Note: OS X 10.4 does not support in-kernel UDBZ. Common options: -srcimagekey, -encryption, and -stdinpass. 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. -norsrcfork don't embed resource fork data. The image will not attach on OS X versions prior to OS X 10.2. hfsanalyze image Print information about an HFS/HFS+ volume. As is usually the case, image can be a /dev entry corresponding to a physical disk. See the NOTE ON DEV ENTRY ACCESS section. Common options: -encryption, -stdinpass, -srcimagekey, and -shadow with friends. mountvol dev_name Attempt to mount the filesystem in dev_name using Disk Arbitration (similar to diskutil mount). XML output is available from -plist. Note that mountvol (rather than mount) will remount a volume after it has been unmounted by unmount. Images are attached and detached; volumes are mounted and unmounted. mountvol undoes a unmount operation. mount/attach can be called on a /dev entry, but it will treat the /dev entry as a disk image to be attached (creating another /dev entry). This is usually undesirable. unmount volume [-force] unmounts a mounted volume without detaching any associated image. volume is a /dev entry or the name of a mountpoint. NOTE: unmount does NOT detach any disk image associated with the volume. Images are attached and detached; volumes are mounted and unmounted. mount (which is a synonym for attach) will NOT remount an image-based volume if the image is already attached but the volume is not mounted (i.e. if unmount has been used on the filesystem). mountvol will remount a volume that has been unmounted by unmount. Options: -force unmount filesystem regardless of open files on that filesystem. Similar to umount -f. imageinfo image Print out information about a disk image. Common options: -encryption, -stdinpass, -srcimagekey, -shadow with friends, and -plist. Options are any of: -format just print out the image format -checksum just print out the image checksum 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, /Network/Library/Plug-ins/DiskImages). -plist is available. internet-enable [-yes] | -no | -query image Enable or disable post-processing for the image. Without arguments, IDME will be enabled. If so enabled, upon first encounter with Disk Copy (on OS X 10.2.3+) or a browser using the feature for a download on OS X 10.3, the image will have its visible contents copied into the directory containing the image and the image will be put into the trash with IDME turned off. Common options: -encryption, -stdinpass, -srcimagekey, and -plist. resize size_spec image Given a read/write partitioned UDIF, if the last partition is Apple_HFS, attempt to resize the partition to the end of the image, or to the last used block in the embedded HFS/HFS+ filesystem (depending on size_spec). resize is often used when a device image needs to be shrunken so that the HFS/HFS+ partition can be converted to CD-R/DVD-R format and still be burned. Note that gaps cannot be reclaimed as resize does not move data. -fsargs can sometimes be used to minimize filesystem-generated gaps. resize can also be used to grow a filesystem and image without bound. 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 with friends, and -plist. Size specifiers: -size ??b|??k|??m|??g|??t??p|??e -sectors sector_count | min | max Specify the number of 512 byte sectors to which the partition should be resized. If this falls outside the min/max values, an error will be returned and the partition will not be resized. min automatically determines the smallest size the partition can be resized to and uses that value. max automatically determines the largest size to which the partition can be grown and then uses that value. Other options: -imageonly only resize the image file, not the partition(s) inside of it. This is the default for UDIF images (more partitions can then be added in the new free space). -partitiononly only resize the partition(s) in the image (including their embedded filesystems). This is the default for NDIF images. For a newlycreated SPUD where the partition fills the image, the partition can only be shrunk. If there is an Apple_Free partition after an existing partition, that partition can be expanded into the space marked by the Apple_Free. Shrinking a partition results in a larger Apple_Free partition. -partitionNumber partitionNumber specifies which partition to resize (UDIF only -- see HISTORY below). partitionNumber is 0-based, but, per hdiutil pmap, partition 0 is the partition 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. Such an image restored to a hard drive will not boot OS 9 nor will it allow OS X to boot on old-world (beige) machines. -limits Displays the minimum, current, and maximum sizes (in 512 byte sectors) that could be passed given possible -imageonly or -partitiononly flags. Does not modify the image. -oldlimits behaves like -limits except that it reports the stretch sizes that OS X version 10.3 would have reported (useful if an image needs to be used with asr(8) on an older system). segment 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. Common options: -encryption, -stdinpass, -srcimagekey, -tgtimagekey, -puppetstrings, and -plist. Options: -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 unqualified 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. See notes with create about not being allowed to overwrite attached images, etc. pmap image_source [-options optstr] display the partition map of an image or device. image_source is either a plain file or special file (i.e. a /dev/disk entry). See the NOTE ON DEV ENTRY ACCESS below. Common options: -encryption, -stdinpass, -srcimagekey, and -shadow with friends. optstr defaults to "xsSgcvk" and can be any combination of the following: r raw - process all without modification x extended - process 2K & 512 entries and merge s sectorize - return all quantities in sectors S sort - sort all entries by block number g genfree - account for all unmapped space c combfree - combine adjacent freespace entries f fixfinal - extend last partition to device end v volume synthesize - synthesize single volumes as a single partition entry k skip zero-length - skip zero length entries K skip void/free - skip all free & void partitions m merge free space - Merge small free partitions into a previous partition if possible i ignore shims - ignore small free partitions caused by block alignment EXAMPLES
Verifying: hdiutil verify myimage.img Verifies an image against its internal checksum. Segmenting: hdiutil segment -segmentSize 10m -o /tmp/aseg 30m.dmg creates aseg.dmg, aseg.002.dmgpart, and aseg.003.dmgpart Converting: hdiutil convert master.dmg -format UDTO -o master Converts master.dmg to a CD-R export image, appending .toast to the filename. hdiutil convert CDmaster.dmg -format UDTO -o CDmaster.cdr Converts CDmaster.dmg to a CD-R export image named CDmaster.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. Burning: hdiutil burn myImage.dmg Burns the image to available 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 an encrypted SPUD without user interaction: echo -n 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 new mounted volume backed by an image: hdiutil create -volname Dick -size 1.3m -fs HFS -attach Moby.dmg 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/Preview.app /Volumes/Moby hdiutil detach /dev/disk2 hdiutil convert -format UDZO Moby.dmg -shadow Using makehybrid. Given the files: albumlist.txt song2.wma song4.m4a song6.mp3 song8.mp3 song1.wma song3.m4a song5.mp3 song7.mp3 Create an HFS+/ISO9660/Joliet hybrid MusicBackup.iso with some common content between filesystems. The HFS+ filesystem, typically 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. The -hide options take glob expressions as expanded by glob(3). hdiutil makehybrid -o MusicBackup.iso Music -hfs -iso -joliet \ -hide-hfs 'Music/*.wma' -hide-joliet 'Music/{*.m4a,*.mp3}' \ -hide-iso 'Music/*.{wma,m4a}' (see also drutil(1) for making CD audio discs) 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 10542 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 sudo mount -ur -t hfs -o perm /dev/disk1s2 /Volumes/myVolume # what if I prefer using /sbin/mount disktool -p disk1s2 # try 'diskutil unmount' on Panther mkdir /Volumes/myVolume Forcing a known image to attach: hdiutil attach -imagekey diskimage-class=CRawDiskImage myBlob.bar ENVIRONMENT
The following environment variables affect hdiutil and DiskImages: com_apple_hdid_verbose enable -verbose behavior for attach. com_apple_hdid_debug enable -debug behavior for attach. com_apple_hdid_nokernel similar to -nokernel but works even with, for example, create -attach. com_apple_hdid_kernel attempt to attach in-kernel first. This is the default behavior for most images, but certain images, such as RAM-based images described in hdid(8), will attach without a user process when they would otherwise have one. (WARNING: ram:// images currently use wired memory when attached in-kernel). com_apple_diskimages_insecureHTTP 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. ERRORS
DiskImages uses many frameworks and can encounter many error codes. In general, it tries to turn these errors numbers into localized strings for the user. For background, intro(2) is a good explanation of the initial 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: [ENXIO] Device not configured. This error is returned by DiskImages when its kernel driver or framework helper cannot be contacted. The former usually means the IOHDIXController kernel extension can't be loaded. The latter usually means Foundation's distributed objects RPC mechanism cannot be configured. DO doesn't work under dead mach bootstrap contexts such as exist in a reattached screen(1) session. Root users can take advantage of StartupItemContext(8) to access the startup item mach bootstrap context. [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 uses this error explicitly when attempting to access a disk image over HTTP that is too large for the server to support Range requests. See hdid(8) for more details. [EAUTH] Authentication error. Used by DiskImages when libcurl(3) is unable to verify its SSL peer. See -insecurehttp for more information. [EBUSY] Resource busy. Used if necessary exclusive access cannot be obtained. For example, returned by create -ov when the image is attached. 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 effective user ID. On the other hand, "permission denied" tends to mean that a particular access mode prevented the operation. USING PERSISTENT SPARSE IMAGES
SPARSE images (and shadow files) were originally designed for the intermediate steps in the creation other images (e.g. UDZO) when final image sizes are unknown. As of OS X 10.3, partially-updated SPARSE images are now properly handled such that they can be safely used for persistent storage. SPARSE images are not recommended for persistent storage on versions of OS X earlier than 10.3.2 and should generally only be used when data sizes are truly unknown. resize can resize an HFS+ filesystem and the image containing it. If more space is needed than is referenced by the hosted filesystem, create -stretch and resize can help to grow or shrink the filesystem in the image. compact improves the experience of using a SPARSE image for persistent storage by reclaiming unused space in the image. Beware that SPARSE images can enhance the effects of any fragmentation in the filesystem. To prevent errors when a filesystem inside of a sparse image has more free space than the volume holding 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 currently 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 (e.g. with unmount and mountvol). NOTE ON DEV ENTRY ACCESS
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 hfsanalyze on it. 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). This may cause apparent hangs while trying to access /dev entries while logged in remotely (an authorization panel is waiting on console). Generally, the /dev/disk node is preferred for imaging devices (e.g. convert or create -srcfolder operations), while /dev/rdisk is usable for the quick pmap or hfsanalyze. 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). COMPATIBILITY
Several new features were introduced into the DiskImages framework with OS X 10.1 and OS X 10.2. Sparse images, encrypted images, and zlib-compressed images all did not exist in OS X 10.0.x but came into being with 10.1. These images will not attach (or will attach read/write allowing for their destruction) on OS X 10.0.x. There are multiple types of sparse, shadow, and encrypted images; various keys (documented above) can be passed to ensure the compatibility desired is achieved (at some cost to performance and reliability). With OS X 10.2, images could be attached without a helper process, image meta-data could be stored as XML, and the default Disk Copy.app "compressed" format became UDZO (UDZO is supported by OS X 10.1 and later). OS X 10.4 introduced bzip2 compression in the UDBZ format which is incompatible with prior systems. SPARSE images should not be expected to be backwards compatible (i.e. expected to attach on versions of OS X older than that which created them). HISTORY
Originally, disk images were invented to electronically store and transmit representations of floppy disks for manufacturing replication. These images are typically referred to as 'Disk Copy 4.2' images, in reference to the application that created these images 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 of the floppy image. NDIF (New Disk Image Format) images were developed to replace the Disk Copy 4.2 and DART image formats, as well as provide the ability to create 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) also began providing highly asymmetric compression ideal for images that were created once and restored many times. Specifically, it decompresses far faster than its compresses while maintaining high compression ratios. UDIF (Universal Disk Image Format) device images go beyond NDIF, allowing the creation of device images which include data that might appear on a given mass storage device (DDM, Apple partition scheme partition map, disk-based drivers, etc). This format allows items such as bootable CD's to be created from an image. UDIF is a flat file format (vs. NDIF which is a dual fork format), and is the native image format for OS X. Raw disk images from other operating systems (e.g. .iso files) can be attached and their filesystems mounted if OS X recognizes the filesystems. They can also be burned with hdiutil burn. WHAT'S NEW In Mac OS X 10.3, most Disk Copy functionality moved to Disk Utility and a new background application DiskImageMounter attaches images for the user. As of Mac OS X 10.4, encrypted images (such as those used for FileVault) can be attached without a user process and image from folder operations no longer require more disk space than the final image. Images containing exotic-to-CD filesystems (such as MS-DOS) can now be burned with burn -synthesize. Significant hdiutil changes in 10.4 include the addition of -puppetstrings to many verbs, -anydevice becoming the default for burn, and signal handlers so that hdiutil can try to clean up before quitting when canceled. SEE ALSO
authopen(1), hdid(8), diskutil, ditto(8), load_hdi(8), ioreg(8), drutil(1), ufs.util(8), msdos.util(8), hfs.util(8), diskarbitrationd(8), /usr/sbin/disktool (run with no arguments for usage), /System/Library/CoreServices/DiskImageMounter.app. Mac OS X 22 Mar 2005 Mac OS X