# <img src="https://cdn.rawgit.com/spack/spack/develop/share/spack/logo/spack-logo.svg" width="64" valign="middle" alt="Spack"/> Spack

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Spack is a multi-platform package manager that builds and installs
multiple versions and configurations of software. It works on Linux,
macOS, and many supercomputers. Spack is non-destructive: installing a
new version of a package does not break existing installations, so many
configurations of the same package can coexist.

Spack offers a simple "spec" syntax that allows users to specify versions
and configuration options. Package files are written in pure Python, and
specs allow package authors to write a single script for many different
builds of the same package.  With Spack, you can build your software
*all* the ways you want to.

See the
[Feature Overview](http://spack.readthedocs.io/en/latest/features.html)
for examples and highlights.

To install spack and your first package, make sure you have Python.
Then:

    $ git clone https://github.com/spack/spack.git
    $ cd spack/bin
    $ ./spack install libelf

Documentation
----------------

[**Full documentation**](http://spack.readthedocs.io/) for Spack is
the first place to look.

Try the
[**Spack Tutorial**](http://spack.readthedocs.io/en/latest/tutorial.html),
to learn how to use spack, write packages, or deploy packages for users
at your site.

See also:
  * [Technical paper](http://www.computer.org/csdl/proceedings/sc/2015/3723/00/2807623.pdf) and
    [slides](https://tgamblin.github.io/files/Gamblin-Spack-SC15-Talk.pdf) on Spack's design and implementation.
  * [Short presentation](https://tgamblin.github.io/files/Gamblin-Spack-Lightning-Talk-BOF-SC15.pdf) from the *Getting Scientific Software Installed* BOF session at Supercomputing 2015.

Get Involved!
------------------------

Spack is an open source project.  Questions, discussion, and
contributions are welcome. Contributions can be anything from new
packages to bugfixes, or even new core features.

### Mailing list

If you are interested in contributing to spack, join the mailing list.
We're using Google Groups for this:

  * [Spack Google Group](https://groups.google.com/d/forum/spack)

### Slack channel

Spack has a Slack channel where you can chat about all things Spack:

  * [Spack on Slack](https://spackpm.slack.com)

[Sign up here](https://spackpm.herokuapp.com) to get an invitation mailed
to you.

### Twitter

You can follow [@spackpm](https://twitter.com/spackpm) on Twitter for
updates. Also, feel free to `@mention` us in in questions or comments
about your own experience with Spack.

### Contributions

Contributing to Spack is relatively easy.  Just send us a
[pull request](https://help.github.com/articles/using-pull-requests/).
When you send your request, make ``develop`` the destination branch on the
[Spack repository](https://github.com/spack/spack).

Your PR must pass Spack's unit tests and documentation tests, and must be
[PEP 8](https://www.python.org/dev/peps/pep-0008/) compliant.  We enforce
these guidelines with [Travis CI](https://travis-ci.org/spack/spack).  To
run these tests locally, and for helpful tips on git, see our
[Contribution Guide](http://spack.readthedocs.io/en/latest/contribution_guide.html).

Spack uses a rough approximation of the
[Git Flow](http://nvie.com/posts/a-successful-git-branching-model/)
branching model.  The ``develop`` branch contains the latest
contributions, and ``master`` is always tagged and points to the latest
stable release.

Authors
----------------
Many thanks go to Spack's [contributors](https://github.com/spack/spack/graphs/contributors).

Spack was created by Todd Gamblin, tgamblin@llnl.gov.

### Citing Spack

If you are referencing Spack in a publication, please cite the following paper:

 * Todd Gamblin, Matthew P. LeGendre, Michael R. Collette, Gregory L. Lee,
   Adam Moody, Bronis R. de Supinski, and W. Scott Futral.
   [**The Spack Package Manager: Bringing Order to HPC Software Chaos**](http://www.computer.org/csdl/proceedings/sc/2015/3723/00/2807623.pdf).
   In *Supercomputing 2015 (SC’15)*, Austin, Texas, November 15-20 2015. LLNL-CONF-669890.

License
----------------

Spack is distributed under the terms of both the MIT license and the
Apache License (Version 2.0). Users may choose either license, at their
option.

All new contributions must be made under both the MIT and Apache-2.0
licenses.

See [LICENSE-MIT](https://github.com/spack/spack/blob/develop/LICENSE-MIT),
[LICENSE-APACHE](https://github.com/spack/spack/blob/develop/LICENSE-APACHE),
[COPYRIGHT](https://github.com/spack/spack/blob/develop/COPYRIGHT), and
[NOTICE](https://github.com/spack/spack/blob/develop/NOTICE) for details.

SPDX-License-Identifier: (Apache-2.0 OR MIT)

LLNL-CODE-647188
