ddrescue (1) Linux Manual Page
NAME
ddrescue – data recovery tool
SYNOPSIS
ddrescue [,options/] ,infile outfile /[,mapfile/]
DESCRIPTION
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.
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,–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
-vgives 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
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.
REPORTING BUGS
Report bugs to bug-ddrescue [at] 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 © 2017 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.