ddrescue - data recovery tool
ddrescue [options] infile outfile
[mapfile]
GNU ddrescue - Data recovery tool. Copies data from one file or
block device to another, trying to rescue the good parts first in case of
read errors.
Always use a mapfile unless you know you won't need it. Without a
mapfile, ddrescue can't resume a rescue, only reinitiate it. NOTE: In
versions of ddrescue prior to 1.20 the mapfile was called 'logfile'. The
format is the same; only the name has changed.
If you reboot, check the device names before restarting ddrescue.
Don't use options '-F' or '-G' without reading the manual first.
- -h, --help
- display this help and exit
- -V, --version
- output version information and exit
- -a,
--min-read-rate=<bytes>
- minimum read rate of good areas in bytes/s
- -A,
--try-again
- mark non-trimmed, non-scraped as non-tried
- -b,
--sector-size=<bytes>
- sector size of input device [default 512]
- -B,
--binary-prefixes
- show binary multipliers in numbers [SI]
- -c,
--cluster-size=<sectors>
- sectors to copy at a time [128]
- -C,
--complete-only
- don't read new data beyond mapfile limits
- -d, --idirect
- use direct disc access for input file
- -D, --odirect
- use direct disc access for output file
- -e,
--max-bad-areas=[+]<n>
- maximum number of [new] bad areas allowed
- -E,
--max-error-rate=<bytes>
- maximum allowed rate of read errors per second
- -f, --force
- overwrite output device or partition
- -F,
--fill-mode=<types>
- fill blocks of given types with data (?*/-+l)
- -G,
--generate-mode
- generate approximate mapfile from partial copy
- -H,
--test-mode=<file>
- set map of good/bad blocks from given mapfile
- -i,
--input-position=<bytes>
- starting position of domain in input file [0]
- -I,
--verify-input-size
- verify input file size with size in mapfile
- -J,
--verify-on-error
- reread latest good sector after every error
- -K,
--skip-size=[<i>][,<max>]
- initial,maximum size to skip on read error
- -L,
--loose-domain
- accept an incomplete domain mapfile
- -m,
--domain-mapfile=<file>
- restrict domain to finished blocks in <file>
- -M, --retrim
- mark all failed blocks as non-trimmed
- -n,
--no-scrape
- skip the scraping phase
- -N, --no-trim
- skip the trimming phase
- -o,
--output-position=<bytes>
- starting position in output file [ipos]
- -O,
--reopen-on-error
- reopen input file after every read error
- -p,
--preallocate
- preallocate space on disc for output file
- -P,
--data-preview[=<lines>]
- show some lines of the latest data read [3]
- -q, --quiet
- suppress all messages
- -r,
--retry-passes=<n>
- exit after <n> retry passes (-1=infinity) [0]
- -R, --reverse
- reverse the direction of all passes
- -s,
--size=<bytes>
- maximum size of input data to be copied
- -S, --sparse
- use sparse writes for output file
- -t,
--truncate
- truncate output file to zero size
- -T,
--timeout=<interval>
- maximum time since last successful read
- -u,
--unidirectional
- run all passes in the same direction
- -v, --verbose
- be verbose (a 2nd -v gives more)
- -w,
--ignore-write-errors
- make fill mode ignore write errors
- -x,
--extend-outfile=<bytes>
- extend outfile size to be at least this long
- -X,
--max-read-errors=<n>
- maximum number of read errors allowed
- -y,
--synchronous
- use synchronous writes for output file
- -Z,
--max-read-rate=<bytes>
- maximum read rate in bytes/s
- --ask
- ask for confirmation before starting the copy
- --cpass=<n>[,<n>]
- select what copying pass(es) to run
- --delay-slow=<interval>
- initial delay before checking slow reads [30]
- --log-events=<file>
- log significant events in <file>
- --log-rates=<file>
- log rates and error sizes in <file>
- --log-reads=<file>
- log all read operations in <file>
- --mapfile-interval=[i][,i]
- save/sync mapfile at given interval [auto]
- --max-slow-reads=<n>
- maximum number of slow reads allowed
- --pause-on-error=<interval>
- time to wait after each read error [0]
- --pause-on-pass=<interval>
- time to wait between passes [0]
- --reset-slow
- reset slow reads if rate rises above min
- --same-file
- allow infile and outfile to be the same file
Numbers may be in decimal, hexadecimal or octal, and may be
followed by a multiplier: s = sectors, k = 1000, Ki = 1024, M = 10^6, Mi =
2^20, etc... Time intervals have the format 1[.5][smhd] or 1/2[smhd].
Exit status: 0 for a normal exit, 1 for environmental problems
(file not found, invalid flags, I/O errors, etc), 2 to indicate a corrupt or
invalid input file, 3 for an internal consistency error (eg, bug) which
caused ddrescue to panic.
Report bugs to bug-ddrescue@gnu.org
Ddrescue home page: http://www.gnu.org/software/ddrescue/ddrescue.html
General help using GNU software: http://www.gnu.org/gethelp
Copyright © 2018 Antonio Diaz Diaz. License GPLv2+: GNU GPL
version 2 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it. There is NO
WARRANTY, to the extent permitted by law.
The full documentation for ddrescue is maintained as a
Texinfo manual. If the info and ddrescue programs are properly
installed at your site, the command
- info ddrescue
should give you access to the complete manual.