2. Using Python on Unix platforms (2024)

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 apackage on all others. However there are certain features you might want to usethat are not available on your distro’s package. You can easily compile thelatest version of Python from source.

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

2.1.2. On FreeBSD and OpenBSD¶

FreeBSD users, to add the package use:
```
pkg install python3
```
See Also
A Beginner's Guide to Installing Python on Mac Web development with Python on Windows How to install Python in Windows?How to Install Python on Mac

OpenBSD users, to add the package use:

pkg_add -r pythonpkg_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

2.2. Building Python¶

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

The build process consists of the usual commands:

./configuremakemake install

Configuration options and caveats for specific Unixplatforms are extensively documented in the README.rst file in theroot of the Python source tree.

2.3. Python-related paths and files¶

These are subject to difference depending on local installation conventions;prefix and exec_prefixare installation-dependent and should be interpreted as for GNU software; theymay 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 directoriescontaining the standard modules.
`prefix/include/pythonversion`,`exec_prefix/include/pythonversion`	Recommended locations of the directoriescontaining the include files needed fordeveloping Python extensions andembedding 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 isusually

#!/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. Custom OpenSSL¶

To use your vendor’s OpenSSL configuration and system trust store, locatethe directory with openssl.cnf file or symlink in /etc. On mostdistribution the file is either in /etc/ssl or /etc/pki/tls. Thedirectory should also contain a cert.pem file and/or a certsdirectory.
```
$ find /etc/ -name openssl.cnf -printf "%h\n"/etc/ssl
```

Download, build, and install OpenSSL. Make sure you use install_sw andnot install. The install_sw target does not overrideopenssl.cnf.

$ curl -O https://www.openssl.org/source/openssl-VERSION.tar.gz$ tar xzf openssl-VERSION$ pushd openssl-VERSION$ ./config \ --prefix=/usr/local/custom-openssl \ --libdir=lib \ --openssldir=/etc/ssl$ make -j1 depend$ make -j8$ make install_sw$ popd

Build Python with custom OpenSSL(see the configure --with-openssl and --with-openssl-rpath options)

$ pushd python-3.x.x$ ./configure -C \ --with-openssl=/usr/local/custom-openssl \ --with-openssl-rpath=auto \ --prefix=/usr/local/python-3.x.x$ make -j8$ make altinstall

Note

Patch releases of OpenSSL have a backwards compatible ABI. You don’t needto recompile Python to update OpenSSL. It’s sufficient to replace thecustom OpenSSL installation with a newer version.