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jdupes

jdupes.com

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Spec score 8.1 #8 of 38 in Duplicate File Finders

What it is

jdupes is a free utility for finding and handling exact duplicate files on Linux, macOS, and Windows. It identifies files that are fully identical rather than matching images, sounds, or other formats by similarity. Matching can use file size, hashes, and byte-for-byte comparison, with optional partial-hash matching. The project says it checks matching data after hashing to reduce the chance of false matches from hash collisions. Found duplicates can be reviewed before deletion, deleted without prompting, linked, summarized, or handled through copy-on-write deduplication. On Linux and Unix, the instructions use command-line directory paths; the project also provides a native Windows port, including support for Unicode. Docker use is documented, and standard output can feed shell scripts. A database can retain scan metadata for repeat runs, though the project labels that feature as under development and notes quirks. The README warns that quick matching skips byte-for-byte checks and can classify non-duplicates as duplicates. It also warns that disabling file-change checks creates a security vulnerability, especially when linking or deleting. jdupes is distributed under the MIT License.

Spec sheet

What it does
jdupes scans directories for duplicate files and can print, delete, link, or deduplicate matching sets.Read 15 Oct 2026 · manpages.debian.org
Purpose
jdupes identifies duplicate files and can delete them, create hard links or symlinks, and perform block-level deduplication.Read 5 Oct 2026 · github.com
Integrations
The README documents Docker usage and says standard output can be piped to shell scripts for processing match sets.Read 5 Oct 2026 · github.com
Support
The README directs bug reports and questions to Jody Bruchon by email.Read 5 Oct 2026 · github.com
License
The software is released under the MIT License.Read 15 Oct 2026 · manpages.debian.org
Founded
2015Read 19 Oct 2026 · jdupes.com
AlternativeTo listing
AlternativeTo categorizes jdupes as a free, open-source duplicate-file finder and says binary releases are available for Windows and Mac OS X.Read 15 Oct 2026 · alternativeto.net
Btrfs deduplication
The dedupe action can invoke filesystem-level block sharing through supported CoW or reflink filesystems.Read 15 Oct 2026 · manpages.debian.org
Container use
The README provides a Docker command example for scanning a mounted directory.Read 5 Oct 2026 · github.com
Data safety
The project says it verifies matching file data after hashing to reduce the risk of false matches from hash collisions.Read 5 Oct 2026 · github.com
Debian versions
Debian Sources lists maintained packages from 1.6 through 1.31.1-1 across current and older releases.Read 15 Oct 2026 · sources.debian.org
Distribution availability
Ubuntu Questing lists jdupes 1.28.0-1 in its Universe repository.Read 15 Oct 2026 · packages.ubuntu.com
Documentation depth
The Debian manpage documents command syntax, actions, filters, linking, dedupe behavior, bug reporting, author, and license.Read 15 Oct 2026 · manpages.debian.org
Exact matches
jdupes matches files that are 100% identical and does not provide similarity matching for images, sounds, or other file formats.Read 5 Oct 2026 · github.com
Exact matching
The program identifies duplicates through file size, partial and full hashes, then byte-for-byte comparison.Read 15 Oct 2026 · manpages.debian.org
File actions
Available actions include prompting to delete duplicates, deleting without prompting, linking duplicates, summarizing results, and copy-on-write deduplication.Read 5 Oct 2026 · github.com
Filtering
Options can exclude hidden files, restrict filesystem boundaries, filter by size, and apply exclusion specifications.Read 15 Oct 2026 · github.com
Full verification
Hash matches are verified against complete file contents before a duplicate is declared.Read 15 Oct 2026 · github.com
Hard links
jdupes can replace duplicate files with hard links to one retained file.Read 15 Oct 2026 · manpages.debian.org
JSON output
The command includes a JSON mode intended for machine-readable output.Read 15 Oct 2026 · github.com
Limit: compatibility
The README warns that jdupes is not a drop-in replacement for fdupes because option meanings differ.Read 15 Oct 2026 · github.com
Limit: destructive options
The documentation warns that quick-hash and partial-only modes can produce false matches and cause data loss when combined with destructive actions.Read 15 Oct 2026 · github.com
Limit: exact matches only
The project states that jdupes does not perform similarity matching or understand image, audio, or other file formats.Read 15 Oct 2026 · github.com
Limit: hard-linking concern
A recent Reddit post reported problems with hard-linking and deleting while using jdupes and sought confirmation before trusting it.Read 15 Oct 2026 · reddit.com
Limit: threading concern
A Reddit user said jdupes was not multithreaded for a large-filesystem use case and considered fclones instead.Read 15 Oct 2026 · reddit.com
Limit: Windows filenames
The project notes that its Windows port supports ANSI filenames rather than Unicode filenames.Read 15 Oct 2026 · github.com
Linux and Unix use
The usage instructions show running jdupes from a command line with one or more directory paths.Read 5 Oct 2026 · github.com
Maintainer
The Debian manual identifies Jody Bruchon as creator and maintainer and credits Adrian Lopez's fdupes as the source project.Read 15 Oct 2026 · manpages.debian.org
News: Debian acceptance
Debian accepted jdupes 1.31.2+really1.31.1-1 into unstable on 2026-10-09 after reverting 1.31.2 for 32-bit build failures.Read 15 Oct 2026 · tracker.debian.org
News: Debian testing
Debian reported jdupes 1.31.2+really1.31.1-1 migrating to testing on 2026-10-14.Read 15 Oct 2026 · tracker.debian.org
News: version release
The official site announced jdupes 1.31.2 and said it fixed an inverted hash-database logic error and added Windows 7 or newer taskbar progress indication.Read 15 Oct 2026 · jdupes.com
Notable limit
The README warns that quick matching skips byte-by-byte verification and may cause non-duplicates to be treated as duplicates.Read 5 Oct 2026 · github.com
Official platform coverage
The maker describes builds for Linux, Windows, Mac OS X, and most Unix-like platforms.Read 15 Oct 2026 · jodybruchon.com
Performance
The project says jdupes was over seven times faster than fdupes 1.51 on average in tests on various data sets.Read 5 Oct 2026 · github.com
Praise: large scans
A Reddit discussion grouped jdupes with tools that remain practical on very large collections by grouping files by size before hashing.Read 15 Oct 2026 · reddit.com
Praise: options
A Reddit commenter recommended jdupes as faster and offering more options than alternatives.Read 15 Oct 2026 · reddit.com
Praise: speed
A Reddit user reported being impressed by jdupes speed in testing and described it as fast on a hard disk.Read 15 Oct 2026 · reddit.com
Recursive scanning
Its command-line interface accepts directory paths and supports recursive traversal.Read 15 Oct 2026 · github.com
Repeat scans
The hash database option stores paths, hashes, and other metadata to speed up repeat runs, and the project labels this feature under development with quirks.Read 5 Oct 2026 · github.com
Runtime dependencies
Ubuntu lists libc6 and libjodycode3t64 as runtime dependencies for its package.Read 15 Oct 2026 · packages.ubuntu.com
Safety check
Normal operation checks whether files changed before scanning or acting, addressing time-of-check/time-of-use risks.Read 15 Oct 2026 · github.com
Security and safety
The project warns that disabling file change checks opens a time-of-check-to-time-of-use security vulnerability, especially for linking or deleting files.Read 5 Oct 2026 · github.com
Sorting controls
Results and automatic actions can be ordered by filename, modification time, or command-parameter order.Read 15 Oct 2026 · manpages.debian.org
Summary reporting
A summarize option reports duplicate information without requiring deletion or linking.Read 15 Oct 2026 · manpages.debian.org
Supported dedupe filesystems
The manual names BTRFS, suitably configured XFS, and Apple APFS as filesystems supporting the dedupe action.Read 15 Oct 2026 · manpages.debian.org
Symbolic links
The tool provides an option to create relative symbolic links for duplicates.Read 15 Oct 2026 · github.com
Windows support
The project provides a native Windows port and notes support for Windows-specific behavior, including Unicode.Read 5 Oct 2026 · github.com

Plans and prices

Free Free command-line duplicate scanning · delete/link/dedupe actions Read 15 Oct 2026 · alternativeto.net
jdupes Free MIT-licensed software · exact duplicate matching Read 5 Oct 2026 · github.com

Every jdupes plan and price →

Strong points and limits

Strong points

  • Free and distributed under the MIT License.
  • Supports Linux, macOS, and Windows.
  • Can delete, link, or deduplicate matching files.
  • Verifies matching data after hashing.
  • Standard output can be piped to shell scripts.

Limits

  • Does not find similar, non-identical files.
  • Quick matching skips byte-for-byte verification.
  • Repeat-scan database is under development and has quirks.
  • No file preview or folder exclusions.

Who it suits

jdupes suits users comfortable with command-line file management who need to locate exact duplicates across local directories. It supports Linux, macOS, and Windows, as well as documented Docker use.

Verdict

jdupes offers several actions for exact duplicate files across three desktop platforms. Avoid quick matching when false duplicate classifications are a concern, and note the warnings around disabling file-change checks.

Where Specifiction places it

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