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ruby-xz is a basic binding to the famous liblzma library, best known for the extreme compression-ratio it's native XZ format achieves. ruby-xz gives you the possibility of creating and extracting XZ archives on any platform where liblzma is installed. No compilation is needed, because ruby-xz is written on top of Ruby's fiddle library (part of the standard library). ruby-xz does not have any dependencies other than Ruby itself.

rubv-xz supports compression and decompression via methods that operate on strings and files, and it also supports compression and decompression on IO streams. the XZ::StreamReader and XZ::StreamWriter offer advanced interfaces that allow you to treat XZ-compressed data as IO streams, both for reading and for writing.

Note: Version 1.0.0 breaks the API quite heavily. Refer to HISTORY.rdoc for details.


Install with gem from your Ruby installation:

gem install ruby-xz

Alternatively, add it to your Gemfile via:

bundle add ruby-xz

If you want to be on the bleeding edge, you can clone the repository and build the most recent code yourself:

git clone
cd ruby-xz
rake gem
gem install pkg/ruby-xz-*.gem


You should be able to find everything you need to use ruby-xz in the documentation. It's small but powerful: You can create and extract whole archive files, compress or decompress whole files, strings, or streams of data.

You can read the documentation on your local gemserver, or browse it online.


require 'xz'

# Compress a file
XZ.compress_file("myfile.txt", "myfile.txt.xz")
# Decompress it
XZ.decompress_file("myfile.txt.xz", "myfile.txt")

# Compress everything you get from a socket (note that there HAS to be a EOF
# sometime, otherwise this will run infinitely)
XZ.compress_stream(socket){|chunk| opened_file.write(chunk)}

# Compress a string
comp = XZ.compress("Mydata")
# Decompress it
data = XZ.decompress(comp)

Have a look at the XZ module's documentation for an in-depth description of what is possible.

Usage with the minitar gem

ruby-xz can be used together with the minitar library (formerly “archive-tar-minitar”) to create XZ-compressed tarballs. This works by employing the IO-like classes XZ::StreamReader and XZ::StreamWriter analogous to how one would use Ruby's “zlib” library together with “minitar”:

require "xz"
require "minitar"

# Create an XZ-compressed tarball"tarball.tar.xz") do |txz|
  Minitar.pack("path/to/directory", txz)

# Unpack it again"tarball.tar.xz") do |txz|
  Minitar.unpack(txz, "path/to/target/directory")


After checking out the repo, run bundle install to install dependencies.

To install this gem onto your local machine, run rake install.

To release a new version:

  • Switch to the development branch.
  • Bump lib/xz/version.rb, run bundle install, then commit the result.
  • Switch to the stable branch.
  • Run git merge development
  • Run rake release, which will create/push a git tag and publish the .gem file to



MIT license; see LICENSE for the full license text.


On November 2021, I volunteered to take over maintenance of this project, which was forked from @Quintus maintained this project until 1.0.0, see HISTORY.rdoc for more details.