Provided by: jdupes_1.13.1-2_amd64 bug

NAME

       jdupes - finds and performs actions upon duplicate files

SYNOPSIS

       jdupes [ options ] FILES and/or DIRECTORIES ...

DESCRIPTION

       Searches  the  given  path(s)  for duplicate files. Such files are found by comparing file
       sizes, then partial and full file hashes,  followed  by  a  byte-by-byte  comparison.  The
       default  behavior  with  no  other  "action  options"  specified (delete, summarize, link,
       dedupe, etc.) is to print sets of matching files.

OPTIONS

       -@ --loud
              output annoying low-level debug info while running

       -0 --printnull
              when printing matches, use null bytes instead  of  CR/LF  bytes,  just  like  'find
              -print0'  does.  This  has  no  effect  with any action mode other than the default
              "print matches" (delete, link, etc. will still print normal  line  endings  in  the
              output.)

       -1 --one-file-system
              do not match files that are on different filesystems or devices

       -A --nohidden
              exclude hidden files from consideration

       -B --dedupe
              issue  the btrfs same-extents ioctl to trigger a deduplication on disk. The program
              must be built with btrfs support for this option to be available

       -C --chunksize=BYTES
              set the I/O chunk size manually; larger values may improve performance on  rotating
              media  by  reducing  the  number  of head seeks required, but also increases memory
              usage and can reduce performance in some cases

       -D --debug
              if this feature is compiled in, show debugging statistics and info at  the  end  of
              program execution

       -d --delete
              prompt user for files to preserve, deleting all others (see CAVEATS below)

       -f --omitfirst
              omit the first file in each set of matches

       -H --hardlinks
              normally,  when  two  or more files point to the same disk area they are treated as
              non-duplicates; this option will change this behavior

       -h --help
              displays help

       -i --reverse
              reverse (invert) the sort order of matches

       -I --isolate
              isolate each command-line parameter from one another; only match if the  files  are
              under different parameter specifications

       -L --linkhard
              replace  all  duplicate  files  with  hardlinks  to  the  first file in each set of
              duplicates

       -m --summarize
              summarize duplicate file information

       -M --printwithsummary
              print matches and summarize the duplicate file information at the end

       -N --noprompt
              when used together with --delete, preserve the first file in each set of duplicates
              and delete the others without prompting the user

       -n --noempty
              exclude  zero-length  files from consideration; this option is the default behavior
              and does nothing (also see -z/--zeromatch)

       -O --paramorder
              parameter order preservation is more  important  than  the  chosen  sort;  this  is
              particularly useful with the -N option to ensure that automatic deletion behaves in
              a controllable way

       -o --order=WORD
              order files according to WORD: time - sort by modification  time  name  -  sort  by
              filename (default)

       -p --permissions
              don't consider files with different owner/group or permission bits as duplicates

       -P --print=type
              print  extra  information  to  stdout; valid options are: early - matches that pass
              early size/permission/link/etc. checks partial - files whose partial  hashes  match
              fullhash - files whose full hashes match

       -Q --quick
              [WARNING:  RISK  OF  DATA  LOSS,  SEE  CAVEATS]  skip byte-for-byte verification of
              duplicate pairs (use hashes only)

       -q --quiet
              hide progress indicator

       -R --recurse:
              for each directory given after this option follow subdirectories encountered within
              (note  the  ':'  at  the  end of option; see the Examples section below for further
              explanation)

       -r --recurse
              for every directory given follow subdirectories encountered within

       -l --linksoft
              replace all duplicate files with  symlinks  to  the  first  file  in  each  set  of
              duplicates

       -S --size
              show size of duplicate files

       -s --symlinks
              follow symlinked directories

       -T --partial-only
              [WARNING:  EXTREME  RISK  OF  DATA  LOSS, SEE CAVEATS] match based on hash of first
              block of file data, ignoring the rest

       -v --version
              display jdupes version and compilation feature flags

       -x --xsize=[+]SIZE (NOTE: deprecated in favor of -X)
              exclude files of size less than SIZE from consideration, or  if  SIZE  is  prefixed
              with  a  '+'  i.e.   jdupes  -x  +226  [files] then exclude files larger than SIZE.
              Suffixes K/M/G can be used.

       -X --exclude=spec:info
              exclude files based on specified criteria; supported specs are:

              `size[+-=]:number[suffix]'
                     Match only if size is greater (+), less  than  (-),  or  equal  to  (=)  the
                     specified  number,  with  an  optional  multiplier  suffix.  The  +/-  and =
                     specifiers can be combined; ex :"size+=:4K" will match if  size  is  greater
                     than  or  equal  to  four  kilobytes  (4096  bytes).  Suffixes supported are
                     K/M/G/T/P/E with a B or iB extension (all case-insensitive); no extension or
                     an  IB  extension  specify  binary multipliers while a B extension specifies
                     decimal multipliers (ex: 4K or 4KiB = 4096, 4KB = 4000.)

       -z --zeromatch
              consider zero-length files to be duplicates; this replaces the old default behavior
              when -n was not specified

       -Z --softabort
              if  the user aborts the program (as with CTRL-C) act on the matches that were found
              before the abort was received. For example, if -L and -Z are specified, all matches
              found prior to the abort will be hard linked. The default behavior without -Z is to
              abort without taking any actions.

NOTES

       A set of arrows are used in hard linking to show  what  action  was  taken  on  each  link
       candidate. These arrows are as follows:

       ---->  This file was successfully hard linked to the first file in the duplicate chain

       -@@->  This file was successfully symlinked to the first file in the chain

       -==->  This file was already a hard link to the first file in the chain

       -//->  Linking this file failed due to an error during the linking process

       Duplicate files are listed together in groups with each file displayed on a separate line.
       The groups are then separated from each other by blank lines.

EXAMPLES

       jdupes a --recurse: b
              will follow subdirectories under b, but not those under a.

       jdupes a --recurse b
              will follow subdirectories under both a and b.

       jdupes -O dir1 dir3 dir2
              will always place 'dir1' results first in any match set (where relevant)

CAVEATS

       Using -1 or --one-file-system prevents matches that cross filesystems, but a more  relaxed
       form  of this option may be added that allows cross-matching for all filesystems that each
       parameter is present on.

       When using -d or --delete, care should be taken to insure against accidental data loss.

       -Z or --softabort used to be --hardabort in jdupes prior to  v1.5  and  had  the  opposite
       behavior.   Defaulting  to  taking  action  on abort is probably not what most users would
       expect. The decision to invert rather than reassign to a different option was made because
       this feature was still fairly new at the time of the change.

       The  -O  or  --paramorder  option allows the user greater control over what appears in the
       first position of a match set, specifically for keeping the -N option  from  deleting  all
       but  one file in a set in a seemingly random way. All directories specified on the command
       line will be used as the sorting order of result  sets  first,  followed  by  the  sorting
       algorithm  set  by  the -o or --order option. This means that the order of all match pairs
       for a single directory specification will retain the old sorting  behavior  even  if  this
       option is specified.

       When  used  together  with  options  -s or --symlink, a user could accidentally preserve a
       symlink while deleting the file it points to.

       The -Q or --quick option only reads each file once, hashes it,  and  performs  comparisons
       based  solely  on  the  hashes.  There is a small but significant risk of a hash collision
       which is the purpose of the failsafe byte-for-byte comparison that this option  explicitly
       bypasses. Do not use it on ANY data set for which any amount of data loss is unacceptable.
       This option is not included in the help text for the program due to its risky nature.  You
       have been warned!

       The  -T  or  --partial-only  option produces results based on a hash of the first block of
       file data in each file, ignoring everything else in the file.  Partial  hash  checks  have
       always been an important exclusion step in the jdupes algorithm, usually hashing the first
       4096 bytes of data and allowing files that are different  at  the  start  to  be  rejected
       early.  In  certain scenarios it may be a useful heuristic for a user to see that a set of
       files has the same size and the same starting data, even if the remaining  data  does  not
       match;  one  example of this would be comparing files with data blocks that are damaged or
       missing such as an incomplete file transfer or checking a data recovery against known-good
       copies  to see what damaged data can be deleted in favor of restoring the known-good copy.
       This option is meant to be used with informational actions and can result in EXTREME  DATA
       LOSS  if  used  with  options  that  delete  files,  create  hard  links, or perform other
       destructive actions on data based on the matching output. Because  of  the  potential  for
       massive  data  destruction,  this  option  MUST BE SPECIFIED TWICE to take effect and will
       error out if it is only specified once.

       Using the -C or --chunksize option to override I/O chunk size can increase performance  on
       rotating  storage  media  by  reducing  "head  thrashing,"  reading larger amounts of data
       sequentially from each file. This tunable size can have bad side effects; the default size
       maximizes  algorithmic  performance without regard to the I/O characteristics of any given
       device and uses a modest amount of memory, but other values may  greatly  increase  memory
       usage  or  incur  a lot more system call overhead. Try several different values to see how
       they affect performance for your hardware and data set. This option does not affect  match
       results  in  any  way, so even if it slows down the file matching process it will not hurt
       anything.

REPORTING BUGS

       Send  all  bug  reports  to   jody@jodybruchon.com   or   use   the   Issue   tracker   at
       http://github.com/jbruchon/jdupes/issues

AUTHOR

       jdupes is a fork of 'fdupes' which is maintained by and contains extra code copyrighted by
       Jody Bruchon <jody@jodybruchon.com>

       Based on 'fdupes' created by Adrian Lopez <adrian2@caribe.net>

                                                                                        JDUPES(1)