[arch-general] An archlinux-python package for managing system default python version?

[杨令]

> From: Chi Hsuan Yen <yan12125 at gmail.com>
> To: General Discussion about Arch Linux <arch-general at archlinux.org>
> Cc:
> Date: Fri, 23 Jan 2015 21:51:00 +0800
> Subject: [arch-general] An archlinux-python package for managing system
default python version?
> Dear Arch enthusiasts,
>
> The package extra/java-runtime-common provides a convenient script
> archlinux-java to handle co-existing JDK/JRE versions. I can use it to
> switch between different versions of java implementations to accomplish
> numerous tasks from testing the compatibilities of my programs to running
> third party applications targeting on different platforms. Now I hope
> there's also a simple script for the same thing but for python. On the
> system, most of the scripts are written for python2 and some other scripts
> are python3-specific. In most cases it's not a problem because I can fix
> the scripts or use some tricks like $PATH to ensure the correct execution
> of the programs. However, in large projects, doing either is
time-consuming
> and costly. Recently I'm building CyanogenMod on Arch Linux. It includes
> lots of python scripts in the build system, and most of them requires
> python2. Using the tip provided on the article about Python on ArchWiki
> prevents lots of problems, but, however, some scripts have the shebang
line
> "#!/usr/bin/env python" or are invoked by some command like
> "/usr/bin/python ...". I have to change the link /usr/bin/python to
> pointing to python2 for further progress on building and changed it back
> for my daily use. If there's an archlinux-python script, lots of time on
> battling the difference between python2 and python3 does not exist
anymore,
> which I believe lots of users can benefit from it. Any ideas?

sudo pacman -S python-virtualenv python2-virtualenv python-virtualenvwrapper

Google how to use them.

Actually virtualenv itself is enough. virtualenvwrapper is a useful
wrapper, so I recommend to use them together.

Here is my virtualenv and virtualenvwrapper configuration in .zshrc. You
can take a look:

# Python virtualenvwrapper
export WORKON_HOME=$HOME/.virtualenvs
#export VIRTUALENVWRAPPER_PYTHON=/usr/bin/python2

if [ -f /usr/bin/virtualenvwrapper.sh ]; then
source /usr/bin/virtualenvwrapper.sh
fi

# Python pip -> virtualenv only
export PIP_REQUIRE_VIRTUALENV=true
export PIP_RESPECT_VIRTUALENV=true

====================
YANG Ling
yangling1984 at gmail.com