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dd and ddrescue
The command line answer. Total control, zero safety net.
- Licence
- Free / open source
- Price
- Free (GPL)
- Platform
- Linux, macOS, BSD; available on Windows via WSL or a live USB
- Current version
- Part of GNU coreutils / GNU ddrescue
- Developer
- GNU project
- Clones the Windows system disk for free
- Yes
- Clone to a smaller drive
- No
- Official site
- www.gnu.org/software/ddrescue/
The verdict
dd copies every byte from one device to another and asks no questions, including "are you sure that is the right disk?". ddrescue is the one you actually want for failing hardware: it skips bad areas, logs what it could not read, and retries them later. Neither is beginner-friendly.
Who it is for
Linux users, forensic copies, and rescuing data from a drive with bad sectors.
Strengths
- Already present on any Linux system, and on any Clonezilla or Rescuezilla USB
- ddrescue is the best free option for reading a physically failing drive
- Byte-exact copies, including unallocated space and partition tables
- Scriptable and completely free
Limitations
- A single typo can destroy the wrong drive with no confirmation prompt
- Copies the whole disk including empty space, so it is slow
- Cannot clone to a smaller drive at all
- No progress bar by default in plain dd
Worth knowing
The usual ddrescue pattern is two passes: a fast first pass that skips errors, then a slower retry pass driven by the map file it wrote.
The interface
assets/img/screenshots/ and swap the src above. See the README in
that folder.
Before you clone anything
The destination drive is erased completely. Confirm which physical disk is which — by
size, model number and serial, not just by drive letter — and keep a separate backup of
anything irreplaceable. Our pre-clone checklist
takes about fifteen minutes and prevents most disasters.