Dd For Mac Os

DiskCopy, bundled with late classic Mac OS versions, opens Apple's own distribution disk images such as file names that end with '.img'. It's worth noting that just because you could once mount a.img file with DiskCopy does not mean that you can mount all of them with it. If the disk image will be used with a Mac that has a solid state drive (SSD) and uses macOS 10.13 or later, choose APFS or APFS (Case-sensitive). If the disk image will be used with a Mac with macOS 10.12 or earlier, choose Mac OS Extended (Journaled) or Mac OS Extended (Case-sensitive, Journaled). I loaded the Mac into recovery mode and ran first aid on the disk, and after doing this it loads he OS without any trouble upon power-on. So for anyone else doing this in the future, 'dd' is a perfectly valid backup and restore method to use for a Mac OS HDD. Here's a little bit of further advice related to dd for anyone who might be about to.

Data Duplicator, convert and copy a file. Copy standard input to the standard output.

Input data is read and written in 512-byte blocks. If input reads are short, input from multiple reads are aggregated to form the output block. When finished, dd displays the number of complete and partial input and output blocks and truncated input records to the standard error output.

ascii, oldascii
The same as the unblock value except that characters are translated from EBCDIC to ASCII before the records
are converted. (These values imply unblock if the operand cbs is also specified.) There are two conversion maps for ASCII. The value ascii specifies the recommended one which is compatible with AT&T System V UNIX. The value oldascii specifies the one used in historic AT&T UNIX and pre-4.3BSD-Reno systems.
block
Treats the input as a sequence of newline or end-of- file terminated variable length records independent of input and output block boundaries. Any trailing new-line character is discarded. Each input record is converted to a fixed length output record where the length is specified by the cbs operand. Input records shorter than the conversion record size are padded with spaces. Input records longer than the conversion record size are truncated. The number of truncated input records, if any, are reported to the standard error output at the completion of the copy.

ebcdic, ibm, oldebcdic, oldibm
The same as the block value except that characters are translated from ASCII to EBCDIC after the records are converted. (These values imply block if the operand cbs is also specified.) There are four conversion maps for EBCDIC. The value ebcdic specifies the recommended one which is compatible with AT&T System V UNIX. The value ibm is a slightly different mapping, which is compatible with the AT&T System V UNIX ibm value. The values oldebcdic and oldibm are maps used in historic AT&T UNIX and pre-4.3BSD-Reno systems.
lcase Transform uppercase characters into lowercase characters.
noerror
Do not stop processing on an input error. When an input error occurs, a diagnostic message followed by the current input and output block counts will be written to the standard error output in the same format as the standard completion message. If the sync conversion is also specified, any missing input data will be replaced with NUL bytes (or with spaces if a block oriented conversion value was specified) and processed as a normal input buffer. If the sync conversion is not
specified, the input block is omitted from the output. On input files which are not tapes or pipes, the file offset will be positioned past the block in which the error occurred using lseek(2).
notrunc
Do not truncate the output file. This will preserve any blocks in the output file not explicitly written by dd. The notrunc value is not supported for tapes.
osync
Pad the final output block to the full output block size. If the input file is not a multiple of the output block size after conversion, this conversion forces the final output block to be the same size as preceding blocks for use on devices that require regularly sized blocks to be written. This option is incompatible with use of the bs=n block size specification.
sparse
If one or more output blocks would consist solely of NUL bytes, try to seek the output file by the required space instead of filling them with NULs, resulting in a sparse file.
swab
Swap every pair of input bytes. If an input buffer has an odd number of bytes, the last byte will be ignored during swapping.
sync
Pad every input block to the input buffer size. Spaces are used for pad bytes if a block oriented conversion value is specified, otherwise NUL bytes are used.
ucase Transform lowercase characters into uppercase characters.
unblock
Treats the input as a sequence of fixed length records independent of input and output block boundaries. The length of the input records is specified by the cbs operand. Any trailing space characters are discarded and a newline character is appended.

Where sizes are specified, a decimal, octal, or hexadecimal number of bytes is expected. If the number ends with a b, k, m, g, or w, the number is multiplied by 512, 1024 (1K), 1048576 (1M), 1073741824 (1G) or the number of bytes in an integer, respectively. Two or more numbers can be separated by an x to indicate a product.

When finished, dd displays the number of complete and partial input and output blocks, truncated input records and odd-length byte-swapping blocks to the standard error output. A partial input block is one where less than the input block size was read. A partial output block is one where less than the output block size was written. Partial output blocks to tape devices are considered fatal errors. Otherwise, the rest of the block will be written. Partial output blocks to character devices will produce a warning message. A truncated input block is one where a variable length record oriented conversion value was specified and the input line was too long to fit in the conversion record or was not newline ter- minated.

Normally, data resulting from input or conversion or both are aggregated into output blocks of the specified size. After the end of input is reached, any remaining output is written as a block. This means that the final output block might be shorter than the output block size.

The name dd is thought to be an allusion to the DD statement found in IBM's Job Control Language (JCL), where the acronym stands for 'Data Description'.

If dd receives a SIGINFO signal, the current input and output block counts will be written to the standard error output in the same format as the standard completion message. If dd receives a SIGINT signal, the current input and output block counts will be written to the standard error output in the same format as the standard completion message and dd will exit.

Examples:

Clone the drive sda onto drive sdb:
$ dd if=/dev/sda of=/dev/sdb

Clone the drive hda onto an image file:
$ dd if=/dev/hda of=/image.img

Copy a CD or DVD disc to a .iso image file, first unmounting the disc:
sudo umount /dev/dvd-device
dd if=/dev/dvd-device of=dvd.iso
bs=2048 conv=sync,notrunc
# dvd-device will typically be dvd for a dvd disc or cdrom for a cdrom disc.

Clone a hard drive to a zipped image file in 100Mb blocks:
$ dd if=/dev/hda bs=100M gzip -c > /image.img

Create a 10 KB file filled with random data (10 x 1K blocks):
$ dd if=/dev/random of=random.bin bs=1024 count=10

Completely wipe the hard drive hdz by overwriting it with random data:
$ dd if=/dev/urandom of=/dev/hdz

“Success isn't something you chase. It's something you have to put forth the effort for constantly. Then maybe it'll come when you least expect it. Most people don't understand that” - Michael Jordan

Related macOS commands:

Apple Disk Utility can create DMG files or ISO files (select the 'CD/DVD Master' option)
cp - Copy one or more files to another location.
cpio - Copy files to and from archives.
hdiutil - Manipulate iso disk images.
install - Copy files and set attributes.
mv - Move or rename files or directories.
tr - Translate, squeeze, and/or delete characters.

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Disk Utility User Guide

Mac

You can use Disk Utility to create a disk image, which is a file that contains other files and folders.

Note: You can burn information to a CD or DVD using the Burn command in the Finder. See Burn CDs and DVDs.

Create a blank disk image for storage

You can create an empty disk image, add data to it, then use it to create disks, CDs, or DVDs.

  1. In the Disk Utility app on your Mac, choose File > New Image > Blank Image.

  2. Enter a filename for the disk image, add tags if necessary, then choose where to save it.

    This is the name that appears in the Finder, where you save the disk image file before opening it.

  3. In the Name field, enter the name for the disk image.

    This is the name that appears on your desktop and in the Finder sidebar, after you open the disk image.

  4. In the Size field, enter a size for the disk image.

  5. Click the Format pop-up menu, then choose the format for the disk:

    • If the disk image will be used with a Mac that has a solid state drive (SSD) and uses macOS 10.13 or later, choose APFS or APFS (Case-sensitive).

    • If the disk image will be used with a Mac with macOS 10.12 or earlier, choose Mac OS Extended (Journaled) or Mac OS Extended (Case-sensitive, Journaled).

    • If the disk image will be used with a Mac or Windows computer and is 32 GB or less, choose MS-DOS (FAT); if it’s over 32 GB, choose ExFAT.

  6. To encrypt the disk image, click the Encryption pop-up menu, then choose an encryption option.

  7. Click the Partitions pop-up menu, then choose a partition layout.

  8. Click the Image Format pop-up menu, then choose an option:

    • Sparse bundle disk image: Same as a sparse disk image (below), but the directory data for the image is stored differently. Uses the .sparsebundle file extension.

    • Sparse disk image: Creates an expandable file that shrinks and grows as needed. No additional space is used. Uses the .sparseimage file extension.

    • Read/write disk image: Allows you to add files to the disk image after it’s created. Uses the .dmg file extension.

    • DVD/CD master: Changes the size of the image to 177 MB (CD 8 cm). Uses the .cdr file extension.

  9. Click Save, then click Done.

    Disk Utility creates the disk image file where you saved it in the Finder and mounts its disk icon on your desktop and in the Finder sidebar.

  10. In the Finder, copy your files to the mounted disk image, then eject it.

  11. Restore the disk image to a disk.

    For more information about disk image types, see the manual (man) page for hdiutil.

Create a disk image from a disk or connected device

You can create a disk image that includes the data and free space on a physical disk or connected device, such as a USB device. For example, if a USB device or volume is 80 GB with 10 GB of data, the disk image will be 80 GB in size and include data and free space. You can then restore that disk image to another volume.

  1. In the Disk Utility app on your Mac, select a disk, volume, or connected device in the sidebar.

  2. Choose File > New Image, then choose “Image from [device name].”

  3. Enter a filename for the disk image, add tags if necessary, then choose where to save it.

    This is the name that appears in the Finder, where you save the disk image file before opening it.

  4. Click the Format pop-up menu, then choose an option:

    • Read-only: The disk image can’t be written to, and is quicker to create and open.

    • Compressed: Compresses data, so the disk image is smaller than the original data. The disk image is read-only.

    • Read/write: Allows you to add files to the disk image after it’s created.

    • DVD/CD master: Can be used with third-party apps. It includes a copy of all sectors of the disk image, whether they’re used or not. When you use a master disk image to create other DVDs or CDs, all data is copied exactly.

  5. To encrypt the disk image, click the Encryption pop-up menu, then choose an encryption option.

  6. Click Save, then click Done.

    Disk Utility creates the disk image file where you saved it in the Finder and mounts its disk icon on your desktop and in the Finder sidebar.

Important: Don’t create a disk image of a disk that you believe to be failing or that contains corrupted information. The disk image may not serve as a reliable backup.

Dd Mac Os Progress

For technical information about creating a restore disk image, see the Apple Software Restore (ASR) manual (man) page.

Create a disk image from a folder or connected device

You can create a disk image that contains the contents of a folder or connected device, such as a USB device. This method doesn’t copy a device’s free space to the disk image. For example, if a USB device or volume is 80 GB with 10 GB of data, the disk image will be 10 GB in size and include only data, not free space. You can then restore that disk image to another volume.

  1. In the Disk Utility app on your Mac, choose File > New Image, then choose Image from Folder.

  2. Select the folder or connected device in the dialog that appears, then click Open.

  3. Enter a filename for the disk image, add tags if necessary, then choose where to save it.

    This is the name that appears in the Finder, where you save the disk image file before opening it.

  4. To encrypt the disk image, click the Encryption pop-up menu, then choose an encryption option.

  5. Click the Image Format pop-up menu, then choose an option:

    • Read-only: The disk image can’t be written to, and is quicker to create and open.

    • Compressed: Compresses data, so the disk image is smaller than the original data. The disk image is read-only.

    • Read/write: Allows you to add files to the disk image after it’s created.

    • DVD/CD master: Can be used with third-party apps. It includes a copy of all sectors of the disk image, whether they’re used or not. When you use a master disk image to create other DVDs or CDs, all data is copied exactly.

    • Hybrid image (HFS+/ISO/UDF): This disk image is a combination of disk image formats and can be used with different file system standards, such as HFS, ISO, and UDF.

  6. Click Save, then click Done.

    Disk Utility creates the disk image file where you saved it in the Finder and mounts its disk icon on your desktop and in the Finder sidebar.

For technical information about creating a restore disk image, see the Apple Software Restore (ASR) manual (man) page.

Create a secure disk image

If you have confidential documents that you don’t want others to see without your permission, you can put them in an encrypted disk image.

Note: If you want to protect the contents of the system disk, turn on FileVault using the FileVault pane of Security & Privacy Preferences.

  1. In the Disk Utility app on your Mac, choose File > New Image > Blank Image.

  2. Enter a filename for the disk image, add tags if necessary, then choose where to save it.

    This is the name that appears in the Finder, where you save the disk image file before opening it.

  3. In the Name field, enter the name for the disk image.

    This is the name that appears on your desktop and in the Finder sidebar, after you open the disk image.

  4. In the Size field, enter a size for the disk image.

  5. Click the Format pop-up menu, then choose a format:

    • If you’re using the encrypted disk image with a Mac computer using macOS 10.13 or later, choose APFS or APFS (Case-sensitive).

    • If you’re using the encrypted disk image with a Mac computer using macOS 10.12 or earlier, choose Mac OS Extended (Journaled) or Mac OS Extended (Case-sensitive, Journaled).

  6. Click the Encryption pop-up menu, then choose an encryption option.

  7. Enter and re-enter a password to unlock the disk image, then click Choose.

    WARNING: If you forget this password, you won’t be able to open the disk image and view any of the files.

  8. Use the default settings for the rest of the options:

    • Click the Partitions pop-up menu, then choose Single partition - GUID Partition Map.

    • Click the Image Format pop-up menu, then choose “read/write” disk image.

  9. Click Save, then click Done.

    Disk Utility creates the disk image file where you saved it in the Finder and mounts its disk icon on your desktop and in the Finder sidebar.

  10. In the Finder , copy the documents you want to protect to the disk image.

  11. If you want to erase the original documents so they can’t be recovered, drag them to the Trash, then choose Finder > Empty Trash.

When you’re finished using the documents on the secure disk image, be sure to eject the disk image. As long as it’s available on your desktop, anyone with access to your computer can use the documents on it.

To access the data in a disk image, double-click it. It appears on your desktop, and you can add, remove, and edit files on it just as you would with a disk.

Dd For Mac Os High Sierra

See alsoAdd a checksum to a disk image using Disk Utility on MacVerify that a disk image’s data isn’t corrupted using Disk Utility on MacRestore a disk image to a disk using Disk Utility on MacConvert a disk image to another format using Disk Utility on Mac