Install a different version of Python

this might be a very simple question but I need your help. I work in a network and I cannot install the programs I want. Anyway, I need to use another version of python, which is installed in the directory /new_version/. Now, when I type "python" in a shell (I use bash) the command point to the version of python installed in the machine I'm working with. I'd love that when I type "python" this command point to the /new_version/ which I've installed. It would be also better if I can call 开发者_开发知识库this "new version" with another command, i.e. python2.

I tried changing the PYTHONPATH in the .bashrc but it didn't work.

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alias newpython="/path/to/your/new_version/python"

Add this to your .bashrc, you can then start the new python with newpython and the standard one with python.

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Add the line

export PATH=/new_version/:$PATH

to your ~/.bashrc (or ~/.bash_profile) file. Then, whenever you run python, it will find the new version first in your PATH. Note this is PATH, not PYTHONPATH. See the comment by @Aaron.

Edit: Only do it this way if you want python to point to the new version. Use an alias as @cularis suggested if you want to call it something different, or make a symlink with:

ln -s /new_version/python /path/to/a/dir/you/add/to/your/path/newpython

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Install virtualenv. With this you can easily set up different Python versions like that:

virtualenv -p /new_version/bin/python

Also, virtualenv enables you to easily install other Python packages via pip install.

And finally, there's a package called tox which can automate testing with different Python versions...