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 python 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/python	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.
~/.pythonrc.py	User-specific initialization file loaded by the user module; not used by default or by most applications.

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 python

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/python 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/.