Python

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Python is the language that powers Portage, eselect, equery, and other tools in Gentoo.

Installation

Since Python is so integral to Gentoo there is little chance it is not installed. Doing so would be like removing the heart from Gentoo. There is occasion where Python must be recompiled in order to add new features or to upgrade.

USE flags

USE flags for dev-lang/python An interpreted, interactive, object-oriented programming language

+ensurepip	Install the ensurepip module that uses bundled wheels to bootstrap pip and setuptools (if disabled, it will be only possible to use venv `--without-pip`)
+ncurses	Add ncurses support (console display library)
+readline	Enable support for libreadline, a GNU line-editing library that almost everyone wants
+sqlite	Add support for sqlite - embedded sql database
+ssl	Add support for SSL/TLS connections (Secure Socket Layer / Transport Layer Security)
+xml	Add support for XML files
berkdb	Add support for sys-libs/db (Berkeley DB)
bluetooth	Build Bluetooth protocol support in socket module
build	!!internal use only!! DO NOT SET THIS FLAG YOURSELF!, used for creating build images and the first half of bootstrapping [make stage1]
debug	Enable extra debug codepaths, like asserts and extra output. If you want to get meaningful backtraces see https://wiki.gentoo.org/wiki/Project:Quality_Assurance/Backtraces
examples	Install examples, usually source code
gdbm	Add support for sys-libs/gdbm (GNU database libraries)
jit	Enable experimental Just-In-Time compilation support.
libedit	Use the libedit library (replacement for readline)
pgo	Optimize the build using Profile Guided Optimization (PGO) by running Python's test suite and collecting statistics based on its performance. This will take longer to build.
tail-call-interp	Enable the tail call interpreter. May lead to better performance but is still new and dependent on latest toolchain versions (Clang 19, GCC 15).
test	Enable dependencies and/or preparations necessary to run tests (usually controlled by FEATURES=test but can be toggled independently)
tk	Add support for Tk GUI toolkit
valgrind	Disable pymalloc when running under dev-debug/valgrind is detected (may incur minor performance penalty even when valgrind is not used)
verify-sig	Verify upstream signatures on distfiles
wininst	Install Windows executables required to create an executable installer for MS Windows

Data provided by the Gentoo Package Database · Last update: 2026-08-17 06:07 More information about USE flags

Emerge

Python is slotted, which means there is more than one version Python that can be installed on a Gentoo system at the same time. Select the version to install by using an : (colon) and the package atom followed by one of the slot numbers:

For example, to install Python 3.4:

root #emerge --ask dev-lang/python:3.4

Configuration

Setting the active interpreter

The active Python interpreter can be set using the eselect python command. First list the available interpreters using list:

root #eselect python list

Select the desired interpreter using set. In this example the second option was chosen:

root #eselect python set 2

Version upgrade

The old python-updater is no longer used.

Before you start, ensure that your system is uptodate:

root #emerge --ask --update --newuse --deep @world

Then, update Python if you hadn't done so already:

root #emerge --ask --update dev-lang/python

In order to tell your system to use the new Python version, update the variables PYTHON_TARGETS and PYTHON_SINGLE_TARGET, for instance in your make.conf (when updating from 3.4 to 3.5):

PYTHON_TARGETS="python2_7 python3_5"

PYTHON_SINGLE_TARGET="python3_5"

and run

root #emerge --ask --update --newuse --deep @world

again. You may be asked to update any remaining python_targets_python3_4 USE flags as well.

Note that many popular packages such as Docker still require PYTHON_SINGLE_TARGET to be set to python2_7 due to various dependencies such as app-text/asciidoc which do not yet support Python 3.

Once your upgrade has completed, you should be able to remove the old Python version using

root #emerge --ask --depclean dev-lang/python

Usage

Invocation

A specific version of the Python interpreter can be invoked from the command-line directly by running:

user $python2.7

Or

user $python3.4

To execute a script with Python 2.x use the following header:

FILE /usr/local/bin/repo

#!/usr/bin/env python2
...

See also

• Bash - The original Linux scripting language.
• Pip - Python's built-in package management system.