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
- https://www.debian.org/doc/manuals/maint-guide/first.en.html
for Debian users
- https://en.opensuse.org/Portal:Packaging
for OpenSuse users
- https://docs-old.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 install python3
OpenBSD users, to add the package use:
pkg_add -r python 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 of the usual commands:
./configure
make
make install
Configuration options and caveats for specific Unix platforms are extensively documented in the README.rst 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
.
2.4. 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. Custom OpenSSL¶
To use your vendor’s OpenSSL configuration and system trust store, locate the directory with
openssl.cnf
file or symlink in/etc
. On most distribution the file is either in/etc/ssl
or/etc/pki/tls
. The directory should also contain acert.pem
file and/or acerts
directory.$ find /etc/ -name openssl.cnf -printf "%h\n" /etc/ssl
Download, build, and install OpenSSL. Make sure you use
install_sw
and notinstall
. Theinstall_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 need to recompile Python to update OpenSSL. It’s sufficient to replace the custom OpenSSL installation with a newer version.