DDRESCUE(1)

NAME
ddrescue - data recovery tool

SYNOPSIS
ddrescue [options] infile outfile [mapfile]

DESCRIPTION
GNU ddrescue is a data recovery tool. It copies data from one file or block device (hard disc, cdrom, etc) 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. Be careful to not specify by mistake an old mapfile from an unrelated rescue.

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.

OPTIONS

-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, --check-input-size
    compare input file size with size in mapfile

-J, --check-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 unordered domain mapfile with gaps

-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

-W, --compare-before-write
    omit superfluous writes in rescue mode

-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

--bad-sector-data=<file>
    treat sectors with <file> data as read errors

--command-mode
    execute commands from standard input

--continue-on-errno=<n>[,<n>]
    treat errno code <n> as non-fatal

--cpass=<range>
    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 command-line options, I/O errors, etc), 2 to indicate a corrupt or invalid input file, 3 for an internal consistency error (e.g., bug) which caused ddrescue to panic.

REPORTING BUGS
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
Copyright © 2025 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.

SEE ALSO
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.