• Duplicate files and directories (and as a by-product unique files).
• Nonstripped Binaries (Binaries with debug symbols; needs to be explicitly enabled).
• Broken symbolic links.
• Empty files and directories (also nested empty directories).
• Files with broken user or group id.

-T --types="list" (default: defaults)

Configure the types of lint rmlint will look for. The list string is a comma-separated list of lint types or lint groups (other separators like semicolon or space also work though).

One of the following groups can be specified at the beginning of the list:

Any of the following lint types can be added individually, or deselected by prefixing with a -:

WARNING: It is good practice to enclose the description in single or double quotes. In obscure cases argument parsing might fail in weird ways, especially when using spaces as separator.

Example:

$ rmlint -T "df,dd"        # Only search for duplicate files and directories
$ rmlint -T "all -df -dd"  # Search for all lint except duplicate files and dirs.

-o --output=spec / -O --add-output=spec (default: -o sh:rmlint.sh -o pretty:stdout -o summary:stdout -o json:rmlint.json)

Configure the way rmlint outputs its results. A spec is in the form format:file or just format. A file might either be an arbitrary path or stdout or stderr. If file is omitted, stdout is assumed. format is the name of a formatter supported by this program. For a list of formatters and their options, refer to the Formatters section below.

If -o is specified, rmlint's default outputs are overwritten. With --O the defaults are preserved. Either -o or -O may be specified multiple times to get multiple outputs, including multiple outputs of the same format.

Examples:

$ rmlint -o json                 # Stream the json output to stdout
$ rmlint -O csv:/tmp/rmlint.csv  # Output an extra csv fle to /tmp

-c --config=spec[=value] (default: none)

Configure a format. This option can be used to fine-tune the behaviour of the existing formatters. See the Formatters section for details on the available keys.

If the value is omitted it is set to a value meaning "enabled".

Examples:

$ rmlint -c sh:link            # Smartly link duplicates instead of removing
$ rmlint -c progressbar:fancy  # Use a different theme for the progressbar

-z --perms[=[rwx]] (default: no check)

Only look into file if it is readable, writable or executable by the current user. Which one of the can be given as argument as one of "rwx".

If no argument is given, "rw" is assumed. Note that r does basically nothing user-visible since rmlint will ignore unreadable files anyways. It's just there for the sake of completeness.

By default this check is not done.

$ rmlint -z rx $(echo $PATH | tr ":" " ") # Look at all executable files in $PATH

-a --algorithm=name (default: blake2b)

Choose the algorithm to use for finding duplicate files. The algorithm can be either paranoid (byte-by-byte file comparison) or use one of several file hash algorithms to identify duplicates. The following hash families are available (in approximate descending order of cryptographic strength):

sha3, blake,

sha,

highway, md

metro, murmur, xxhash

The weaker hash functions still offer excellent distribution properties, but are potentially more vulnerable to malicious crafting of duplicate files.

The full list of hash functions (in decreasing order of checksum length) is:

512-bit: blake2b, blake2bp, sha3-512, sha512

384-bit: sha3-384,

256-bit: blake2s, blake2sp, sha3-256, sha256, highway256, metro256, metrocrc256

160-bit: sha1

128-bit: md5, murmur, metro, metrocrc

64-bit: highway64, xxhash.

The use of 64-bit hash length for detecting duplicate files is not recommended, due to the probability of a random hash collision.

-p --paranoid / -P --less-paranoid (default)

Increase or decrease the paranoia of rmlint's duplicate algorithm. Use -p if you want byte-by-byte comparison without any hashing.

-v --loud / -V --quiet

Increase or decrease the verbosity. You can pass these options several times. This only affects rmlint's logging on stderr, but not the outputs defined with -o. Passing either option more than three times has no further effect.

-g --progress / -G --no-progress (default)

Show a progressbar with sane defaults.

Convenience shortcut for -o progressbar -o summary -o sh:rmlint.sh -o json:rmlint.json -VVV.

NOTE: This flag clears all previous outputs. If you want additional outputs, specify them after this flag using -O.

-D --merge-directories (default: disabled)

Makes rmlint use a special mode where all found duplicates are collected and checked if whole directory trees are duplicates. Use with caution: You always should make sure that the investigated directory is not modified during rmlint's or its removal scripts run.

IMPORTANT: Definition of equal: Two directories are considered equal by rmlint if they contain the exact same data, no matter how the files containing the data are named. Imagine that rmlint creates a long, sorted stream out of the data found in the directory and compares this in a magic way to another directory. This means that the layout of the directory is not considered to be important by default. Also empty files will not count as content. This might be surprising to some users, but remember that rmlint generally cares only about content, not about any other metadata or layout. If you want to only find trees with the same hierarchy you should use --honour-dir-layout / -j.

Output is deferred until all duplicates were found. Duplicate directories are printed first, followed by any remaining duplicate files that are isolated or inside of any original directories.

--rank-by applies for directories too, but 'p' or 'P' (path index) has no defined (i.e. useful) meaning. Sorting takes only place when the number of preferred files in the directory differs.

NOTES:

-j --honour-dir-layout (default: disabled)

Only recognize directories as duplicates that have the same path layout. In other words: All duplicates that build the duplicate directory must have the same path from the root of each respective directory. This flag makes no sense without --merge-directories.

-y --sort-by=order (default: none)

During output, sort the found duplicate groups by criteria described by order. order is a string that may consist of one or more of the following letters:

The letter may also be written uppercase (similar to -S / --rank-by) to reverse the sorting. Note that rmlint has to hold back all results to the end of the run before sorting and printing.

-w --with-color (default) / -W --no-with-color

Use color escapes for pretty output or disable them. If you pipe rmlints output to a file -W is assumed automatically.

-h --help / -H --show-man

Show a shorter reference help text (-h) or the full man page (-H).

--version

Print the version of rmlint. Includes git revision and compile time features. Please include this when giving feedback to us.

-s --size=range (default: 1 )

Only consider files as duplicates in a certain size range. The format of range is min-max, where both ends can be specified as a number with an optional multiplier. The available multipliers are:

The size format is about the same as dd(1) uses. A valid example would be: "100KB-2M". This limits duplicates to a range from 100 Kilobyte to 2 Megabyte.

It's also possible to specify only one size. In this case the size is interpreted as "bigger or equal". If you want to filter for files up to this size you can add a - in front (-s -1M == -s 0-1M).

Edge case: The default excludes empty files from the duplicate search. Normally these are treated specially by rmlint by handling them as other lint. If you want to include empty files as duplicates you should lower the limit to zero:

$ rmlint -T df --size 0

-d --max-depth=depth (default: INF)

Only recurse up to this depth. A depth of 1 would disable recursion and is equivalent to a directory listing. A depth of 2 would also consider all children directories and so on.

-l --hardlinked (default) / --keep-hardlinked / -L --no-hardlinked

Hardlinked files are treated as duplicates by default (--hardlinked). If --keep-hardlinked is given, rmlint will not delete any files that are hardlinked to an original in their respective group. Such files will be displayed like originals, i.e. for the default output with a "ls" in front. The reasoning here is to maximize the number of kept files, while maximizing the number of freed space: Removing hardlinks to originals will not allocate any free space.

If --no-hardlinked is given, only one file (of a set of hardlinked files) is considered, all the others are ignored; this means, they are not deleted and also not even shown in the output. The "highest ranked" of the set is the one that is considered.

-f --followlinks / -F --no-followlinks / -@ --see-symlinks (default)

-f will always follow symbolic links. If file system loops occurs rmlint will detect this. If -F is specified, symbolic links will be ignored completely, if -@ is specified, rmlint will see symlinks and treats them like small files with the path to their target in them. The latter is the default behaviour, since it is a sensible default for --merge-directories.

-x --no-crossdev / -X --crossdev (default)

Stay always on the same device (-x), or allow crossing mountpoints (-X). The latter is the default.

-r --hidden / -R --no-hidden (default) / --partial-hidden

Also traverse hidden directories? This is often not a good idea, since directories like .git/ would be investigated, possibly leading to the deletion of internal git files which in turn break a repository. With --partial-hidden hidden files and folders are only considered if they're inside duplicate directories (see --merge-directories) and will be deleted as part of it.

-b --match-basename

Only consider those files as dupes that have the same basename. See also man 1 basename. The comparison of the basenames is case-insensitive.

-B --unmatched-basename

Only consider those files as dupes that do not share the same basename. See also man 1 basename. The comparison of the basenames is case-insensitive.

-e --match-with-extension / -E --no-match-with-extension (default)

Only consider those files as dupes that have the same file extension. For example two photos would only match if they are a .png. The extension is compared case-insensitive, so .PNG is the same as .png.

-i --match-without-extension / -I --no-match-without-extension (default)

Only consider those files as dupes that have the same basename minus the file extension. For example: banana.png and Banana.jpeg would be considered, while apple.png and peach.png won't. The comparison is case-insensitive.

-n --newer-than-stamp=<timestamp_filename> / -N --newer-than=<iso8601_timestamp_or_unix_timestamp>

Only consider files (and their size siblings for duplicates) newer than a certain modification time (mtime). The age barrier may be given as seconds since the epoch or as ISO8601-Timestamp like 2014-09-08T00:12:32+0200.

-n expects a file from which it can read the timestamp. After rmlint run, the file will be updated with the current timestamp. If the file does not initially exist, no filtering is done but the stampfile is still written.

-N, in contrast, takes the timestamp directly and will not write anything.

Note that rmlint will find duplicates newer than timestamp, even if the original is older. If you want only find duplicates where both original and duplicate are newer than timestamp you can use find(1):

Note: you can make rmlint write out a compatible timestamp with:

-k --keep-all-tagged / -K --keep-all-untagged

Don't delete any duplicates that are in tagged paths (-k) or that are in non-tagged paths (-K). (Tagged paths are those that were named after //).

-m --must-match-tagged / -M --must-match-untagged

Only look for duplicates of which at least one is in one of the tagged paths. (Paths that were named after //).

Note that the combinations of -kM and -Km are prohibited by rmlint. See https://github.com/sahib/rmlint/issues/244 for more information.

-S --rank-by=criteria (default: pOma)

Sort the files in a group of duplicates into originals and duplicates by one or more criteria. Each criteria is defined by a single letter (except r and x which expect a regex pattern after the letter). Multiple criteria may be given as string, where the first criteria is the most important. If one criteria cannot decide between original and duplicate the next one is tried.

Alphabetical sort will only use the basename of the file and ignore its case. One can have multiple criteria, e.g.: -S am will choose first alphabetically; if tied then by mtime. Note: original path criteria (specified using //) will always take first priority over -S options.

For more fine grained control, it is possible to give a regular expression to sort by. This can be useful when you know a common fact that identifies original paths (like a path component being src or a certain file ending).

To use the regular expression you simply enclose it in the criteria string by adding <REGULAR_EXPRESSION> after specifying r or x. Example: -S 'r<.*\.bak$>' makes all files that have a .bak suffix original files.

Warning: When using r or x, try to make your regex to be as specific as possible! Good practice includes adding a $ anchor at the end of the regex.

Tips:

--replay

Read an existing json file and re-output it. When --replay is given, rmlint does no input/output on the filesystem, even if you pass additional paths. The paths you pass will be used for filtering the --replay output.

This is very useful if you want to reformat, refilter or resort the output you got from a previous run. Usage is simple: Just pass --replay on the second run, with other changed to the new formatters or filters. Pass the .json files of the previous runs additionally to the paths you ran rmlint on. You can also merge several previous runs by specifying more than one .json file, in this case it will merge all files given and output them as one big run.

If you want to view only the duplicates of certain subdirectories, just pass them on the commandline as usual.

The usage of // has the same effect as in a normal run. It can be used to prefer one .json file over another. However note that running rmlint in --replay mode includes no real disk traversal, i.e. only duplicates from previous runs are printed. Therefore specifying new paths will simply have no effect. As a security measure, --replay will ignore files whose mtime changed in the meantime (i.e. mtime in the .json file differs from the current one). These files might have been modified and are silently ignored.

By design, some options will not have any effect. Those are:

NOTE: In --replay mode, a new .json file will be written to rmlint.replay.json in order to avoid overwriting rmlint.json.

-C --xattr

Shortcut for --xattr-read, --xattr-write, --write-unfinished. This will write a checksum and a timestamp to the extended attributes of each file that rmlint hashed. This speeds up subsequent runs on the same data set. Please note that not all filesystems may support extended attributes and you need write support to use this feature.

See the individual options below for more details and some examples.

--xattr-read / --xattr-write / --xattr-clear

Read or write cached checksums from the extended file attributes. This feature can be used to speed up consecutive runs.

CAUTION: This could potentially lead to false positives if file contents are somehow modified without changing the file modification time. rmlint uses the mtime to determine the modification timestamp if a checksum is outdated. This is not a problem if you use the clone or reflink operation on a filesystem like btrfs. There an outdated checksum entry would simply lead to some duplicate work done in the kernel but would do no harm otherwise.

NOTE: Many tools do not support extended file attributes properly, resulting in a loss of the information when copying the file or editing it.

NOTE: You can specify --xattr-write and --xattr-read at the same time. This will read from existing checksums at the start of the run and update all hashed files at the end.

Usage example:

$ rmlint large_file_cluster/ -U --xattr-write   # first run should be slow.
$ rmlint large_file_cluster/ --xattr-read       # second run should be faster.
# Or do the same in just one run:
$ rmlint large_file_cluster/ --xattr

-U --write-unfinished

Include files in output that have not been hashed fully, i.e. files that do not appear to have a duplicate. Note that this will not include all files that rmlint traversed, but only the files that were chosen to be hashed.

This is mainly useful in conjunction with --xattr-write/read. When re-running rmlint on a large dataset this can greatly speed up a re-run in some cases. Please refer to --xattr-read for an example.

If you want to output unique files, please look into the uniques output formatter.

-t --threads=N (default: 16)

The number of threads to use during file tree traversal and hashing. rmlint probably knows better than you how to set this value, so just leave it as it is. Setting it to 1 will also not make rmlint a single threaded program.

-u --limit-mem=size

Apply a maximum number of memory to use for hashing and --paranoid. The total number of memory might still exceed this limit though, especially when setting it very low. In general rmlint will however consume about this amount of memory plus a more or less constant extra amount that depends on the data you are scanning.

The size-description has the same format as for --size, therefore you can do something like this (use this if you have 1GB of memory available):

$ rmlint -u 512M # Limit paranoid mem usage to 512 MB

-q --clamp-low=[fac.tor|percent%|offset] (default: 0) / -Q --clamp-top=[fac.tor|percent%|offset] (default: 1.0)

The argument can be either passed as factor (a number with a . in it), a percent value (suffixed by %) or as absolute number or size spec, like in --size.

Only look at the content of files in the range of from low to (including) high. This means, if the range is less than -q 0% to -Q 100%, than only partial duplicates are searched. If the file size is less than the clamp limits, the file is ignored during traversing. Be careful when using this function, you can easily get dangerous results for small files.

This is useful in a few cases where a file consists of a constant sized header or footer. With this option you can just compare the data in between. Also it might be useful for approximate comparison where it suffices when the file is the same in the middle part.

Example:

$ rmlint -q 10% -Q 512M # Only read the last 90% of a file, but read at max. 512MB

-Z --mtime-window=T (default: -1)

Only consider those files as duplicates that have the same content and the same modification time (mtime) within a certain window of T seconds. If T is 0, both files need to have the same mtime. For T=1 they may differ one second and so on. If the window size is negative, the mtime of duplicates will not be considered. T may be a floating point number.

However, with three (or more) files, the mtime difference between two duplicates can be bigger than the mtime window T, i.e. several files may be chained together by the window. Example: If T is 1, the four files fooA (mtime: 00:00:00), fooB (00:00:01), fooC (00:00:02), fooD (00:00:03) would all belong to the same duplicate group, although the mtime of fooA and fooD differs by 3 seconds.

--with-fiemap (default) / --without-fiemap

Enable or disable reading the file extents on rotational disk in order to optimize disk access patterns. If this feature is not available, it is disabled automatically.

•

csv: Output all found lint as comma-separated-value list.

Available options:

•

available options:

•

json: Print a JSON-formatted dump of all found reports. Outputs all lint as a json document. The document is a list of dictionaries, where the first and last element is the header and the footer. Everything between are data-dictionaries.

Available options:

This formatter is extremely useful if you're in need of scripting more complex behaviour, that is not directly possible with rmlint's built-in options. A very handy tool here is jq. Here is an example to output all original files directly from a rmlint run:

$ rmlint -o | json jq -r '.[1:-1][] | select(.is_original) | .path'

• py: Outputs a python script and a JSON document, just like the json formatter. The JSON document is written to .rmlint.json, executing the script will make it read from there. This formatter is mostly intended for complex use-cases where the lint needs special handling that you define in the python script. Therefore the python script can be modified to do things standard rmlint is not able to do easily.
• uniques: Outputs all unique paths found during the run, one path per line. This is often useful for scripting purposes.

  Available options:

•

stamp:

Outputs a timestamp of the time rmlint was run. See also the --newer-than and --newer-than-stamp file option.

Available options:

•

progressbar: Shows a progressbar. This is meant for use with stdout or stderr [default].

See also: -g (--progress) for a convenience shortcut option.

Available options:

• pretty: Shows all found items in realtime nicely colored. This formatter is activated as default.
• summary: Shows counts of files and their respective size after the run. Also list all written output files.
• fdupes: Prints an output similar to the popular duplicate finder fdupes(1). At first a progressbar is printed on stderr. Afterwards the found files are printed on stdout; each set of duplicates gets printed as a block separated by newlines. Originals are highlighted in green. At the bottom a summary is printed on stderr. This is mostly useful for scripts that were set up for parsing fdupes output. We recommend the json formatter for every other scripting purpose.

  Available options:

rmlint --gui

Start the optional graphical frontend to rmlint called Shredder.

This will only work when Shredder and its dependencies were installed. See also: http://rmlint.readthedocs.org/en/latest/gui.html

The gui has its own set of options, see --gui --help for a list. These should be placed at the end, ie rmlint --gui [options] when calling it from commandline.

rmlint --hash [paths...]

Make rmlint work as a multi-threaded file hash utility, similar to the popular md5sum or sha1sum utilities, but faster and with more algorithms. A set of paths given on the commandline or from stdin is hashed using one of the available hash algorithms. Use rmlint --hash -h to see options.

rmlint --equal [paths...]

Check if the paths given on the commandline all have equal content. If all paths are equal and no other error happened, rmlint will exit with an exit code 0. Otherwise it will exit with a nonzero exit code. All other options can be used as normal, but note that no other formatters (sh, csv etc.) will be executed by default. At least two paths need to be passed.

Note: This even works for directories and also in combination with paranoid mode (pass -pp for byte comparison); remember that rmlint does not care about the layout of the directory, but only about the content of the files in it. At least two paths need to be given to the commandline.

By default this will use hashing to compare the files and/or directories.

rmlint --dedupe [-r] [-v|-V] <src> <dest>

If the filesystem supports files sharing physical storage between multiple files, and if src and dest have same content, this command makes the data in the src file appear the dest file by sharing the underlying storage.

This command is similar to cp --reflink=always <src> <dest> except that it (a) checks that src and dest have identical data, and it makes no changes to dest's metadata.

Running with -r option will enable deduplication of read-only [btrfs] snapshots (requires root).

rmlint --is-reflink [-v|-V] <file1> <file2>

Tests whether file1 and file2 are reflinks (reference same data). This command makes rmlint exit with one of the following exit codes:

• Check the current working directory for duplicates.

  $ rmlint

• Show a progressbar:

  $ rmlint -g

• Quick re-run on large datasets using different ranking criteria on second run:

  $ rmlint large_dir/ # First run; writes rmlint.json

  $ rmlint --replay rmlint.json large_dir -S MaD

• Merge together previous runs, but prefer the originals to be from b.json and make sure that no files are deleted from b.json:

  $ rmlint --replay a.json // b.json -k

• Search only for duplicates and duplicate directories

  $ rmlint -T "df,dd" .

• Compare files byte-by-byte in current directory:

  $ rmlint -pp .

• Find duplicates with same basename (excluding extension):

  $ rmlint -e

• Do more complex traversal using find(1).

  $ find /usr/lib -iname '*.so' -type f | rmlint - # find all duplicate .so files

  $ find /usr/lib -iname '*.so' -type f -print0 | rmlint -0 # as above but handles filenames with newline character in them

  $ find ~/pics -iname '*.png' | ./rmlint - # compare png files only

• Limit file size range to investigate:

  $ rmlint -s 2GB # Find everything >= 2GB

  $ rmlint -s 0-2GB # Find everything < 2GB

• Only find writable and executable files:

  $ rmlint --perms wx

• Reflink if possible, else hardlink duplicates to original if possible, else replace duplicate with a symbolic link:

  $ rmlint -c sh:link

• Inject user-defined command into shell script output:

  $ rmlint -o sh -c sh:cmd='echo "original:" "$2" "is the same as" "$1"'

• Use shred to overwrite the contents of a file fully:

  $ rmlint -c 'sh:cmd=shred -un 10 "$1"'

• Use data as master directory. Find only duplicates in backup that are also in data. Do not delete any files in data:

  $ rmlint backup // data --keep-all-tagged --must-match-tagged

• Compare if the directories a b c and are equal

  $ rmlint --equal a b c && echo "Files are equal" || echo "Files are not equal"

• Test if two files are reflinks

  $ rmlint --is-reflink a b && echo "Files are reflinks" || echo "Files are not reflinks".

• Cache calculated checksums for next run. The checksums will be written to the extended file attributes:

  $ rmlint --xattr

• Produce a list of unique files in a folder:

  $ rmlint -o uniques

• Produce a list of files that are unique, including original files ("one of each"):

  $ rmlint t -o json -o uniques:unique_files | jq -r '.[1:-1][] | select(.is_original) | .path' | sort > original_files $ cat unique_files original_files

• Sort files by a user-defined regular expression

# Always keep files with ABC or DEF in their basename,
# dismiss all duplicates with tmp, temp or cache in their names
# and if none of those are applicable, keep the oldest files instead.
$ ./rmlint -S 'x<.*(ABC|DEF).*>X<.*(tmp|temp|cache).*>m' /some/path

•

Sort files by adding priorities to several user-defined regular expressions:

# Unlike the previous snippet, this one uses priorities:
# Always keep files in ABC, DEF, GHI by following that particular order of
# importance (ABC has a top priority), dismiss all duplicates with
# tmp, temp, cache in their paths and if none of those are applicable,
# keep the oldest files instead.
$ rmlint -S 'r<.*ABC.*>r<.*DEF.*>r<.*GHI.*>R<.*(tmp|temp|cache).*>m' /some/path

1.

False Positives: Depending on the options you use, there is a very slight risk of false positives (files that are erroneously detected as duplicate). The default hash function (blake2b) is very safe but in theory it is possible for two files to have then same hash. If you had 10^73 different files, all the same size, then the chance of a false positive is still less than 1 in a billion. If you're concerned just use the --paranoid (-pp) option. This will compare all the files byte-by-byte and is not much slower than blake2b (it may even be faster), although it is a lot more memory-hungry.

2.

File modification during or after rmlint run: It is possible that a file that rmlint recognized as duplicate is modified afterwards, resulting in a different file. If you use the rmlint-generated shell script to delete the duplicates, you can run it with the -p option to do a full re-check of the duplicate against the original before it deletes the file. When using -c sh:hardlink or -c sh:symlink care should be taken that a modification of one file will now result in a modification of all files. This is not the case for -c sh:reflink or -c sh:clone. Use -c sh:link to minimise this risk.

• find(1)
• rm(1)
• cp(1)

•

http://rmlint.rtfd.org

• gdb --ex run -ex bt --args rmlint -vvv [your_options]
• valgrind --leak-check=no rmlint -vvv [your_options]

• git clone git@github.com:sahib/rmlint.git
• cd rmlint
• scons GDB=1 DEBUG=1
• sudo scons install # Optional

• Christopher <sahib> Pahl 2010-2017 (https://github.com/sahib)
• Daniel <SeeSpotRun> T. 2014-2017 (https://github.com/SeeSpotRun)