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1.2 A Simple Example

The setup script is usually quite simple, although since it's written in Python, there are no arbitrary limits to what you can do with it, though you should be careful about putting arbitrarily expensive operations in your setup script. Unlike, say, Autoconf-style configure scripts, the setup script may be run multiple times in the course of building and installing your module distribution.

If all you want to do is distribute a module called `foo`, contained in a file foo.py, then your setup script can be as simple as this:

    from distutils.core import setup
    setup(name='foo',
          version='1.0',
          py_modules=['foo'],
          )

Some observations:

- most information that you supply to the Distutils is supplied as keyword arguments to the `setup()` function
- those keyword arguments fall into two categories: package metadata (name, version number) and information about what's in the package (a list of pure Python modules, in this case)
- modules are specified by module name, not filename (the same will hold true for packages and extensions)
- it's recommended that you supply a little more metadata, in particular your name, email address and a URL for the project (see section 2 for an example)

To create a source distribution for this module, you would create a setup script, setup.py, containing the above code, and run:

    python setup.py sdist

which will create an archive file (e.g., tarball on Unix, ZIP file on Windows) containing your setup script setup.py, and your module foo.py. The archive file will be named foo-1.0.tar.gz (or .zip), and will unpack into a directory foo-1.0.

If an end-user wishes to install your `foo` module, all she has to do is download foo-1.0.tar.gz (or .zip), unpack it, and--from the foo-1.0 directory--run

    python setup.py install

which will ultimately copy foo.py to the appropriate directory for third-party modules in their Python installation.

This simple example demonstrates some fundamental concepts of the Distutils. First, both developers and installers have the same basic user interface, i.e. the setup script. The difference is which Distutils commands they use: the `sdist` command is almost exclusively for module developers, while `install` is more often for installers (although most developers will want to install their own code occasionally).

If you want to make things really easy for your users, you can create one or more built distributions for them. For instance, if you are running on a Windows machine, and want to make things easy for other Windows users, you can create an executable installer (the most appropriate type of built distribution for this platform) with the `bdist_wininst` command. For example:

    python setup.py bdist_wininst

will create an executable installer, foo-1.0.win32.exe, in the current directory.

Other useful built distribution formats are RPM, implemented by the `bdist_rpm` command, Solaris pkgtool (`bdist_pkgtool`), and HP-UX swinstall (`bdist_sdux`). For example, the following command will create an RPM file called foo-1.0.noarch.rpm:

    python setup.py bdist_rpm

(The `bdist_rpm` command uses the `rpm` executable, therefore this has to be run on an RPM-based system such as Red Hat Linux, SuSE Linux, or Mandrake Linux.)

You can find out what distribution formats are available at any time by running

    python setup.py bdist --help-formats