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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 libary). ruby-xz does not have any dependencies other than Ruby itself.

ruby-xz supports both “intuitive” (de)compression by providing methods to directly operate on strings and files, but also allows you to operate directly on IO streams (see the various methods of the XZ module). On top of that, ruby-xz offers an advanced interface that allows you to treat XZ-compressed data as IO streams, both for reading and for writing. See the XZ::StreamReader and XZ::StreamWriter classes for more information on this.

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


Install it the way you install all your gems.

$ gem install ruby-xz

Alternatively, you can clone the repository and build the most recent code yourself:

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


The documentation of the XZ module is well and you should be able to find everything you need to use ruby-xz. As said, it's not big, but powerful: You can create and extract whole archive files, compress or decompress streams of data or just plain strings.

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


You have to require the “xz.rb” file:

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”. Example:

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")
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MIT license; see LICENSE for the full license text.