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diffoscope - in-depth comparison of files, archives, and directories


diffoscope --help
diffoscope [OPTIONS] [--json output_diff] path1 path2
diffoscope [OPTIONS] diff
diffoscope [OPTIONS] < diff


diffoscope will try to get to the bottom of what makes files or directories different. It will recursively unpack archives of many kinds and transform various binary formats into more human readable form to compare them. It can compare two tarballs, ISO images, or PDF just as easily.

It can be scripted through error codes, and a report can be produced with the detected differences. The report can be text or HTML. When no type of report has been selected, diffoscope defaults to write a text report on the standard output.

diffoscope was initially started by the "reproducible builds" Debian project and now being developed as part of the (wider) ???Reproducible Builds??? initiative. It is meant to be able to quickly understand why two builds of the same package produce different outputs. diffoscope was previously named debbindiff.

See the COMMAND-LINE EXAMPLES section further below to get you started, as well as more detailed explanations of all the command-line options. The same information is also available in /usr/share/doc/diffoscope/README.rst or similar.

First file or directory to compare. Specify "-" to read a diffoscope diff from stdin.
Second file or directory to compare. If omitted, no comparison is done but instead we read a diffoscope diff from path1 and will output this in the formats specified by the rest of the command line.

optional arguments:

Display debug messages
Open the Python pdb debugger in case of crashes
--status-fd FD
Send machine-readable status to file descriptor FD
--progress, --no-progress
Show an approximate progress bar. Default: yes if stdin is a tty, otherwise no.
Disable most default output limits and diff calculation limits.

output types:

Write plain text output to given file (use - for stdout)
--text-color WHEN
When to output color diff. WHEN is one of {never, auto, always}. Default: auto, meaning yes if the output is a terminal, otherwise no.
If there was no difference, then output an empty diff for each output type that was specified. In --text output, an empty file is written.
Write HTML report to given file (use - for stdout)
--html-dir OUTPUT_DIR
Write multi-file HTML report to given directory
--css URL
Link to an extra CSS for the HTML report
--jquery URL
URL link to jQuery, for --html and --html-dir output. If this is a non-existent relative URL, diffoscope will create a symlink to a system installation. (Paths searched: /usr/share/javascript/jquery/jquery.js.) If not given, --html output will not use JS but --htmldir will if it can be found; give "disable" to disable JS on all outputs.
Write JSON text output to given file (use - for stdout)
--markdown OUTPUT_FILE
Write Markdown text output to given file (use - for stdout)
--restructured-text OUTPUT_FILE
Write RsT text output to given file (use - for stdout)
--difftool TOOL
Compare differences one-by-one using the specified external command similar to git-difftool(1)
--profile OUTPUT_FILE
Write profiling info to given file (use - for stdout)

output limits:

--max-text-report-size BYTES
Maximum bytes written in --text report. (0 to disable, default: 0)
--max-report-size BYTES
Maximum bytes of a report in a given format, across all of its pages. Note that some formats, such as --html, may be restricted by even smaller limits such as --max-page-size. (0 to disable, default: 41943040)
--max-diff-block-lines LINES
Maximum number of lines output per unified-diff block, across all pages. (0 to disable, default: 1024)
--max-page-size BYTES
Maximum bytes of the top-level (--html-dir) or sole (--html) page. (default: 41943040, remains in effect even with --no-default-limits)
--max-page-diff-block-lines LINES
Maximum number of lines output per unified-diff block on the top-level (--html-dir) or sole (--html) page, before spilling it into a child page (--html-dir) or skipping the rest of the diff block. (default: 128, remains in effect even with --no-default-limits)

diff calculation:

Treat absent files as empty
--exclude GLOB_PATTERN
Exclude files whose names (including any directory part) match GLOB_PATTERN. Use this option to ignore files based on their names.
--exclude-command REGEX_PATTERN
Exclude commands that match REGEX_PATTERN. For example '^readelf.*\s--debug-dump=info' can take a long time and differences here are likely secondary differences caused by something represented elsewhere. Use this option to disable commands that use a lot of resources.
--exclude-directory-metadata {auto,yes,no,recursive}
Exclude directory metadata. Useful if comparing files whose filesystem-level metadata is not intended to be distributed to other systems. This is true for most distributions package builders, but not true for the output of commands such as `make install`. Metadata of archive members remain un-excluded except if "recursive" choice is set. Use this option to ignore permissions, timestamps, xattrs etc. Default: False if comparing two directories, else True. Note that "file" metadata actually a property of its containing directory, and is not relevant when distributing the file across systems.
--diff-mask REGEX_PATTERN
Replace/unify substrings that match regular expression REGEX_PATTERN from output strings before applying diff. For example, to filter out a version number or changed path.
--fuzzy-threshold FUZZY_THRESHOLD
Threshold for fuzzy-matching (0 to disable, 60 is default, 400 is high fuzziness)
--tool-prefix-binutils PREFIX
Prefix for binutils program names, e.g. "aarch64-linux-gnu-" for a foreign-arch binary or "g" if you're on a non-GNU system.
--max-diff-input-lines LINES
Maximum number of lines fed to diff(1) (0 to disable, default: 4194304)
--max-container-depth DEPTH
Maximum depth to recurse into containers. (Cannot be disabled for security reasons, default: 50)
--max-diff-block-lines-saved LINES
Maximum number of lines saved per diff block. Most users should not need this, unless you run out of memory. This truncates diff(1) output before emitting it in a report, and affects all types of output, including --text and --json. (0 to disable, default: 0)
--use-dbgsym WHEN
When to automatically use corresponding -dbgsym packages when comparing .deb files. WHEN is one of {no, auto, yes}. Default: auto, meaning yes if two .changes or .buildinfo files are specified, otherwise no.
Force recursing into the depths of file formats even if files have the same content, only really useful for debugging diffoscope. Default: False

information commands:

--help, -h
Show this help and exit
Show program's version number and exit
--list-tools [DISTRO]
Show external tools required and exit. DISTRO can be one of {arch, debian, FreeBSD, guix}. If specified, the output will list packages in that distribution that satisfy these dependencies.
List packages needed for Debian in 'substvar' format.
--list-missing-tools [DISTRO]
Show missing external tools and exit. DISTRO can be one of {arch, debian, FreeBSD, guix}. If specified, the output will list packages in that distribution that satisfy these dependencies.

file formats supported:

Android APK files, Android boot images, Apple Xcode
mobile provisioning files, ar(1) archives, Berkeley DB database files, bzip2 archives, character/block devices, ColorSync colour profiles (.icc), Coreboot CBFS filesystem images, cpio archives, Dalvik .dex files, Debian .buildinfo files, Debian .changes files, Debian source packages (.dsc), Device Tree Compiler blob files, directories, ELF binaries, ext2/ext3/ext4/btrfs/fat filesystems, FreeDesktop Fontconfig cache files, FreePascal files (.ppu), Gettext message catalogues, GHC Haskell .hi files, GIF image files, Git repositories, GNU R database files (.rdb), GNU R Rscript files (.rds), Gnumeric spreadsheets, GPG keybox databases, Gzipped files, Hierarchical Data Format database, ISO 9660 CD images, Java .class files, Java .jmod modules, JavaScript files, JPEG images, JSON files, LLVM IR bitcode files, LZ4 compressed files, MacOS binaries, Microsoft Windows icon files, Microsoft Word .docx files, Mono 'Portable Executable' files, Mozilla-optimized .ZIP archives, Multimedia metadata, OCaml interface files, Ogg Vorbis audio files, OpenOffice .odt files, OpenSSH public keys, OpenWRT package archives (.ipk), PDF documents, PE32 files, PGP signatures, PGP signed/encrypted messages, PNG images, PostScript documents, Public Key Cryptography Standards (PKCS) files (version #7), RPM archives, Rust object files (.deflate), SQLite databases, SquashFS filesystems, symlinks, tape archives (.tar), tcpdump capture files (.pcap), text files, TrueType font files, WebAssembly binary module, XML binary schemas (.xsb), XML files, XZ compressed files, ZIP archives and Zstandard compressed files.

diffoscope homepage:





Exit status is 0 if inputs are the same, 1 if different, 2 if trouble.


To compare two files in-depth and produce an HTML report, run something like:

$ diffoscope --html output.html build1.changes build2.changes

diffoscope will exit with 0 if there's no differences and 1 if there are.

diffoscope can also compare non-existent files:

$ diffoscope /nonexistent

To get all possible options, run:

$ diffoscope --help

If you have enough RAM, you can improve performance by running:

$ TMPDIR=/run/shm diffoscope very-big-input-0/ very-big-input-1/

By default this allowed to use up half of RAM; for more add something like:

tmpfs   /run/shm    tmpfs   size=80%    0   0

to your /etc/fstab; see man mount for details.


diffoscope requires Python 3 and the following modules available on PyPI: libarchive-c, python-magic.

The various comparators rely on external commands being available. To get a list of them, please run:

$ diffoscope --list-tools


Lunar, Reiner Herrmann, Chris Lamb, Mattia Rizzolo, Ximin Luo, Helmut Grohne, Holger Levsen, Daniel Kahn Gillmor, Paul Gevers, Peter De Wachter, Yasushi SHOJI, Clemens Lang, Ed Maste, Joachim Breitner, Mike McQuaid. Baptiste Daroussin, Levente Polyak.


Please report bugs and send patches through the Debian bug tracking system against the diffoscope package: <>

For more instructions, see CONTRIBUTING.rst in this directory.

Join the users and developers mailing-list: <>

diffoscope website is at <>


diffoscope is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

diffoscope is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with diffoscope. If not, see <>.


July 2020 diffoscope 150