# 2. Using Python on Unix platforms

## 2.1. Getting and installing the latest version of Python

### 2.1.1. On Linux

Python comes preinstalled on most Linux distributions, and is available as a package on all others. However there are certain features you might want to use that are not available on your distro’s package. You can easily compile the latest version of Python from source.

In the event that Python doesn’t come preinstalled and isn’t in the repositories as well, you can easily make packages for your own distro. Have a look at the following links:

See also

http://www.debian.org/doc/manuals/maint-guide/first.en.html
  for Debian users
http://en.opensuse.org/Portal:Packaging
  for OpenSuse users
http://docs.fedoraproject.org/en-US/Fedora_Draft_Documentation/0.1/html/RPM_Guide/ch-creating-rpms.html
  for Fedora users
http://www.slackbook.org/html/package-management-making-packages.html
  for Slackware users

### 2.1.2. On FreeBSD and OpenBSD

- FreeBSD users, to add the package use:

      pkg_add -r python

- OpenBSD users use:

      pkg_add ftp://ftp.openbsd.org/pub/OpenBSD/4.2/packages/<insert your architecture here>/python-<version>.tgz

  For example i386 users get the 2.5.1 version of Python using:

      pkg_add ftp://ftp.openbsd.org/pub/OpenBSD/4.2/packages/i386/python-2.5.1p2.tgz

### 2.1.3. On OpenSolaris

You can get Python from OpenCSW. Various versions of Python are available and can be installed with e.g. `pkgutil -i python27`.

## 2.2. Building Python

If you want to compile CPython yourself, first thing you should do is get the source. You can download either the latest release’s source or just grab a fresh clone. (If you want to contribute patches, you will need a clone.)

The build process consists in the usual

    ./configure
    make
    make install

invocations. Configuration options and caveats for specific Unix platforms are extensively documented in the README file in the root of the Python source tree.

Warning

`make install` can overwrite or masquerade the `python3` binary. `make altinstall` is therefore recommended instead of `make install` since it only installs `exec_prefix/bin/pythonversion`.

## 2.3. Python-related paths and files

These are subject to difference depending on local installation conventions; `prefix` (`${prefix}`) and `exec_prefix` (`${exec_prefix}`) are installation-dependent and should be interpreted as for GNU software; they may be the same.

For example, on most Linux systems, the default for both is `/usr`.

File/directory | Meaning
--- | ---
`exec_prefix/bin/python3` | Recommended location of the interpreter.
`prefix/lib/pythonversion`, `exec_prefix/lib/pythonversion` | Recommended locations of the directories containing the standard modules.
`prefix/include/pythonversion`, `exec_prefix/include/pythonversion` | Recommended locations of the directories containing the include files needed for developing Python extensions and embedding the interpreter.

## 2.4. Miscellaneous

To easily use Python scripts on Unix, you need to make them executable, e.g. with

    $ chmod +x script

and put an appropriate Shebang line at the top of the script. A good choice is usually

    #!/usr/bin/env python3

which searches for the Python interpreter in the whole `PATH`. However, some Unices may not have the env command, so you may need to hardcode `/usr/bin/python3` as the interpreter path.

To use shell commands in your Python scripts, look at the `subprocess` module.

## 2.5. Editors

Vim and Emacs are excellent editors which support Python very well. For more information on how to code in Python in these editors, look at:

- http://www.vim.org/scripts/script.php?script_id=790
- http://sourceforge.net/projects/python-mode

Geany is an excellent IDE with support for a lot of languages. For more information, read: http://www.geany.org/

Komodo edit is another extremely good IDE. It also has support for a lot of languages. For more information, read http://komodoide.com/.