Linux下python多版本多环境介绍

 一、python多版本配置说明

安装python相关依赖

[root@centos6 ~]# yum install -y gcc make patch gdbm-devel openssl-devel sqlite-devel readline-devel zlib-devel bzip2-devel

安装git工具

[root@centos6 ~]# yum install -y git

创建python用户

[root@centos6 ~]# useradd python

切换到python用户

[root@centos6 ~]# su - python

从GitHub上拉取pyenv脚本并执行

[python@centos6 ~]$ curl -L https://raw.githubusercontent.com/pyenv/pyenv-installer/master/bin/pyenv-installer|bash

通过加入以下内容到python用户的   ~/.bash_profile  文件中最后，使pyenv自动加载

export PATH="/home/python/.pyenv/bin:$PATH"
eval "$(pyenv init -)"
eval "$(pyenv virtualenv-init -)"

使加入的内容生效

[python@centos6 ~]$ source ~/.bash_profile

命令行执行可以获取pyenv相关的命令说明

[python@centos6 ~]$ pyenv
pyenv 1.1.5
Usage: pyenv <command> [<args>]

Some useful pyenv commands are:
   commands    List all available pyenv commands
   local       Set or show the local application-specific Python version
   global      Set or show the global Python version
   shell       Set or show the shell-specific Python version
   install     Install a Python version using python-build
   uninstall   Uninstall a specific Python version
   rehash      Rehash pyenv shims (run this after installing executables)
   version     Show the current Python version and its origin
   versions    List all Python versions available to pyenv
   which       Display the full path to an executable
   whence      List all Python versions that contain the given executable

See `pyenv help <command>' for information on a specific command.
For full documentation, see: https://github.com/pyenv/pyenv#readme

可以安装多个python版本，然后切换

查看当前python版本

[python@centos6 ~]$ python -V
Python 2.6.6

列出所有可用版本

[python@centos6 ~]$ pyenv install -l

安装指定版本

[python@centos6 ~]$ pyenv install 3.6.3 -v

注：

当这种在线方式安装太慢时，可以选择使用缓存安装，也就是把需要安装的对应源码包下好，放入/home/python/.pyenv/cache  目录下，cache目录不存在时创建即可

[python@centos6 ~]$ mkdir -p /home/python/.pyenv/cache
[python@centos6 ~]$ ll /home/python/.pyenv/cache/
total 38724
-rw-r--r-- 1 python python 16974296 Nov 17 10:19 Python-3.6.3.tar.xz
-rw-r--r-- 1 python python 22673115 Nov 17 10:19 Python-3.6.3.tgz
[python@centos6 ~]$ pyenv install 3.6.3 -v

安装完成后，查看python版本（有 * 代码当前生效的python版本，system就是系统默认版本，这里是python2.6.6）

[python@centos6 ~]$ pyenv versions
* system (set by /home/python/.pyenv/version)
  3.6.3

切换设置python版本，一般建议用python local设置

pyenv global 3.6.3
注意：root用户下，尽量不适用global，会改变全局的python版本

pyenv shell 3.6.3
只作用于当前会话

python local 3.6.3
设置从当前工作目录开始向下递归继承该设置

这里演示python local的功能

[python@centos6 ~]$ mkdir test    #在家目录新建一个test目录
[python@centos6 ~]$ ll
total 4
drwxrwxr-x 2 python python 4096 Nov 17 18:28 test
[python@centos6 ~]$ cd test/        #切换到test目录
[python@centos6 test]$ pyenv local 3.6.3
[python@centos6 test]$ pyenv versions
  system
* 3.6.3 (set by /home/python/test/.python-version)
[python@centos6 test]$ python -V    #这里应该是有bug，重新登录或就正常了
Python 2.6.6
[python@centos6 test]$ python -V
Python 3.6.3

#进入test的子目录，也继承了python版本设置
[python@centos6 test]$ mkdir child
[python@centos6 test]$ cd child/
[python@centos6 child]$ pyenv versions
  system
* 3.6.3 (set by /home/python/test/.python-version)
[python@centos6 child]$ python -V
Python 3.6.3
#进入其他目录，python版本然是系统默认版本
[python@centos6 ~]$ pyenv versions
* system (set by /home/python/.pyenv/version)
  3.6.3
[python@centos6 ~]$ python -V
Python 2.6.6

二、python多环境配置说明

创建一个3.6.3版本的独立空间环境

[python@centos6 ~]$ pyenv virtualenv 3.6.3 martin    #最后的空间名，自己随意指定
Requirement already satisfied: setuptools in /home/python/.pyenv/versions/3.6.3/envs/martin/lib/python3.6/site-packages
Requirement already satisfied: pip in /home/python/.pyenv/versions/3.6.3/envs/martin/lib/python3.6/site-packages
[python@centos6 ~]$ pyenv versions    #查看所有安装的python版本
* system (set by /home/python/.pyenv/version)
  3.6.3
  3.6.3/envs/martin
  martin
[python@centos6 ~]$ cd test/
[python@centos6 test]$ pyenv local martin    #设置当前目录的python版本
(martin) [python@centos6 test]$ pyenv versions    #查看切换后的默认版本情况，设置独立空间环境后，命令提示符前面会多一个自己设置的独立空间的名字
  system
  3.6.3
  3.6.3/envs/martin
* martin (set by /home/python/test/.python-version)

配置好独立空间后，安装的包存在独立目录下

(martin) [python@centos6 test]$ pip -V
pip 9.0.1 from /home/python/.pyenv/versions/3.6.3/envs/martin/lib/python3.6/site-packages (python 3.6)    #独立空间的包存在该目录下

三、安装pip工具

切换到其他目录，当提示匹配命令不存在时，安装pip

官方文档：https://pip.pypa.io/en/stable/installing/

[python@centos6 ~]$ pip -V
pip 9.0.1 from /home/python/.pyenv/versions/3.6.3/lib/python3.6/site-packages (python 3.6)

[python@centos6 ~]$ pip -V
pip 9.0.1 from /usr/lib/python2.6/site-packages (python 2.6)

使用pip安装包

pip 通用配置，更改包搜索源
[python@abc ~]$ cat /home/python/.pip/pip.conf
[global]
index-url=https://mirrors.aliyun.com/pypi/simple/
trusted-host=mirrors.aliyun.com

列出pip已安装的包
pip list

导出已安装的包到requirements格式文件里
pip freeze > requirement

按照所给的requirements格式文件中的包名按照包
pip install -r requirement