linux上有两个版本的python.如何使 2.7 成为默认值 [英] Two versions of python on linux. how to make 2.7 the default

问题描述

我的 linuxbox 上有两个版本的 python:

I've got two versions of python on my linuxbox:

$python
Python 2.6.6 (r266:84292, Jul 10 2013, 22:48:45) 
[GCC 4.4.7 20120313 (Red Hat 4.4.7-3)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> 


$ /usr/local/bin/python2.7
Python 2.7.3 (default, Oct  8 2013, 15:53:09) 
[GCC 4.4.7 20120313 (Red Hat 4.4.7-3)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> 

$ which python
/usr/bin/python
$ ls -al /usr/bin/python
-rwxr-xr-x. 2 root root 4864 Jul 10 22:49 /usr/bin/python

如何使 2.7 成为默认版本，以便当我输入 python 时，它会将我置于 2.7 中?

How can I make 2.7 be the default version so when I type python it puts me in 2.7?

推荐答案

您可能实际上并不想更改默认的 Python.

You probably don't actually want to change your default Python.

您的发行版在 /usr/bin 中安装了一个标准系统 Python，并且可能有依赖于此的脚本存在，并由 #!/usr/bin/env python.您可以通常在 2.7 中运行 Python 2.6 脚本，但您愿意冒险吗?

Your distro installed a standard system Python in /usr/bin, and may have scripts that depend on this being present, and selected by #! /usr/bin/env python. You can usually get away with running Python 2.6 scripts in 2.7, but do you want to risk it?

最重要的是，玩弄/usr/bin 会破坏包管理器管理包的能力.并且更改 PATH 中目录的顺序将影响除 Python 之外的许多其他内容.(实际上，/usr/local/bin 位于 /usr/bin 之前更为常见，这可能是您真正想要的——但如果您拥有它反过来说，大概有一个很好的理由.)

On top of that, monkeying with /usr/bin can break your package manager's ability to manage packages. And changing the order of directories in your PATH will affect a lot of other things besides Python. (In fact, it's more common to have /usr/local/bin ahead of /usr/bin, and it may be what you actually want—but if you have it the other way around, presumably there's a good reason for that.)

但是当您键入 python 时，您不需要需要更改默认 Python 以让系统运行 2.7.

But you don't need to change your default Python to get the system to run 2.7 when you type python.

首先可以设置一个shell别名:

First, you can set up a shell alias:

alias python=/usr/local/bin/python2.7

在提示符下输入，或者如果您希望更改持久化，则将其放入您的 ~/.bashrc 中，现在当 you 输入 python 它运行您选择的 2.7，但是当您系统上的某些程序尝试使用 /usr/bin/env python 运行脚本时，它运行标准的 2.6.

Type that at a prompt, or put it in your ~/.bashrc if you want the change to be persistent, and now when you type python it runs your chosen 2.7, but when some program on your system tries to run a script with /usr/bin/env python it runs the standard 2.6.

或者，只需从您的 2.7(或针对不同项目的单独 venv)创建一个虚拟环境)，并在 venv 内完成您的工作.

Alternatively, just create a virtual environment out of your 2.7 (or separate venvs for different projects), and do your work inside the venv.

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