Provided by: rdfind_1.4.1-1build2_amd64 
NAME
rdfind - finds duplicate files
SYNOPSIS
rdfind [ options ] directory1 | file1 [ directory2 | file2 ] ...
DESCRIPTION
rdfind finds duplicate files across and/or within several directories. It calculates
checksum only if necessary. rdfind runs in O(Nlog(N)) time with N being the number of
files.
If two (or more) equal files are found, the program decides which of them is the original
and the rest are considered duplicates. This is done by ranking the files to each other
and deciding which has the highest rank. See section RANKING for details.
By default, no action is taken besides creating a file with the detected files and showing
the possible amount of saved space.
If you need better control over the ranking than given, you can use some preprocessor
which sorts the file names in desired order and then run the program using xargs. See
examples below for how to use find and xargs in conjunction with rdfind.
To include files or directories that have names starting with -, use rdfind ./- to not
confuse them with options.
RANKING
Given two or more equal files, the one with the highest rank is selected to be the
original and the rest are duplicates. The rules of ranking are given below, where the
rules are executed from start until an original has been found. Given two files A and B
which have equal size and content, the ranking is as follows:
If A was found while scanning an input argument earlier than than B, A is higher ranked.
If A was found at a directory depth lower than B, A is higher ranked (A is closer to the
root).
if A and B are found during scanning of the same input argument and share the same
directory depth, the one that ranks highest depends on if deterministic operation is
enabled. This is on by default, see option -deterministic). If enabled, which one ranks
highest is unspecified but deterministic. If disabled, the one that was reported first
from the file system is highest ranked.
OPTIONS
Searching options etc:
-ignoreempty true|false
Ignore empty files. Setting this to true (the default) is equivalent to -minsize 1,
false is equivalent to -minsize 0.
-minsize N
Ignores files with less than N bytes. Default is 1, meaning empty files are
ignored.
-followsymlinks true|false
Follow symlinks. Default is false.
-removeidentinode true|false
Removes items found which have identical inode and device ID. Default is true.
-checksum md5|sha1|sha256
What type of checksum to be used: md5, sha1 or sha256. The default is sha1 since
version 1.4.0.
-deterministic true|false
If set (the default), sort files of equal rank in an unspecified but deterministic
order. This makes the behaviour independent of in which order files are listed when
querying the file system.
Action options:
-makesymlinks true|false
Replace duplicate files with symbolic links. Default is false.
-makehardlinks true|false
Replace duplicate files with hard links. Default is false.
-makeresultsfile true|false
Make a results file in the current directory. Default is true. If the file exists,
it is overwritten.
-outputname name
Make the results file name to be "name" instead of the default results.txt.
-deleteduplicates true|false
Delete (unlink) files. Default is false.
General options:
-sleep Xms
Sleeps X milliseconds between reading each file, to reduce load. Default is 0 (no
sleep). Note that only a few values are supported at present: 0,1-5,10,25,50,100
milliseconds.
-n, -dryrun true|false
Displays what should have been done, don't actually delete or link anything.
Default is false.
-h, -help, --help
Displays a brief help message.
-v, -version, --version
Displays the version number.
EXAMPLES
Search for duplicate files in the home directory and a backup directory:
rdfind ~ /mnt/backup
Delete duplicates in a backup directory:
rdfind -deleteduplicates true /mnt/backup
Search for duplicate files in directories called foo:
find . -type d -name foo -print0 |xargs -0 rdfind
FILES
results.txt (the default name is results.txt and can be changed with option outputname,
see above) The results file results.txt will contain one row per duplicate file found,
along with a header row explaining the columns. A text describes why the file is
considered a duplicate:
DUPTYPE_UNKNOWN some internal error
DUPTYPE_FIRST_OCCURRENCE the file that is considered to be the original.
DUPTYPE_WITHIN_SAME_TREE files in the same tree (found when processing the directory in
the same input argument as the original)
DUPTYPE_OUTSIDE_TREE the file is found during processing another input argument than the
original.
ENVIRONMENT
DIAGNOSTICS
EXIT VALUES
0 on success, nonzero otherwise.
BUGS/FEATURES
When specifying the same directory twice, it keeps the first encountered as the most
important (original), and the rest as duplicates. This might not be what you want.
The symlink creates absolute links. This might not be what you want. To create relative
links instead, you may use the symlinks (2) command, which is able to convert absolute
links to relative links.
Older versions unfortunately contained a misspelling on the word occurrence. This is now
corrected (since 1.3), which might affect user scripts parsing the output file written by
rdfind.
SECURITY CONSIDERATIONS
Avoid manipulating the directories while rdfind is reading. rdfind is quite brittle in
that case. Especially, when deleting or making links, rdfind can be subject to a symlink
attack. Use with care!
AUTHOR
Paul Dreik 2006-2018, reachable at rdfind@pauldreik.se Rdfind can be found at
https://rdfind.pauldreik.se/
Do you find rdfind useful? Drop me a line! It is always fun to hear from people who
actually use it and what data collections they run it on.
THANKS
Several persons have helped with suggestions and improvements: Niels Möller, Carl Payne
and Salvatore Ansani. Thanks also to you who tested the program and sent me feedback.
VERSION
1.4.1 (release date 2018-11-12)
COPYRIGHT
This program is distributed under GPLv2 or later, at your option.
SEE ALSO
md5sum(1), sha1sum(1), find(1), symlinks(2)