DOKK / manpages / debian 10 / fdupes / fdupes.1.en
FDUPES(1) General Commands Manual FDUPES(1)

fdupes - finds duplicate files in a given set of directories

fdupes [ options ] DIRECTORY ...

Searches the given path for duplicate files. Such files are found by comparing file sizes and MD5 signatures, followed by a byte-by-byte comparison.

for every directory given follow subdirectories encountered within
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)
follow symlinked directories
normally, when two or more files point to the same disk area they are treated as non-duplicates; this option will change this behavior
exclude zero-length files from consideration
omit the first file in each set of matches
exclude hidden files from consideration
-1 --sameline
list each set of matches on a single line
show size of duplicate files
summarize duplicate files information
hide progress indicator
prompt user for files to preserve, deleting all others (see CAVEATS below)
when used together with --delete, preserve the first file in each set of duplicates and delete the others without prompting the user
delete duplicates as they are encountered, without grouping into sets; implies --noprompt
don't consider files with different owner/group or permission bits as duplicates
order files according to WORD: time - sort by mtime, name - sort by filename
reverse order while sorting
display fdupes version
displays help


Unless -1 or --sameline is specified, duplicate files are listed together in groups, each file displayed on a separate line. The groups are then separated from each other by blank lines.

When -1 or --sameline is specified, spaces and backslash characters (\) appearing in a filename are preceded by a backslash character.

will follow subdirectories under b, but not those under a.
will follow subdirectories under both a and b.

If fdupes returns with an error message such as fdupes: error invoking md5sum it means the program has been compiled to use an external program to calculate MD5 signatures (otherwise, fdupes uses internal routines for this purpose), and an error has occurred while attempting to execute it. If this is the case, the specified program should be properly installed prior to running fdupes.

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

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

Furthermore, when specifying a particular directory more than once, all files within that directory will be listed as their own duplicates, leading to data loss should a user preserve a file without its "duplicate" (the file itself!).

Adrian Lopez <>