1.创建python的虚拟环境

[root@python ~]# mkdir -p /virtualenvs

• 安装虚拟环境virtualenv

  [root@python ~]#   pip3 install virtualenv -i https://pypi.tuna.tsinghua.edu.cn/simple/     
  

• 安装虚拟环境扩展包

  [root@python   virtualenvs]# pip3 install virtualenvwrapper    -i https://pypi.tuna.tsinghua.edu.cn/simple/      
  

2. 修改用户家目录下的配置文件.bashrc，添加如下内容

• 修改配置文件

  #查找一下安装的虚拟环境扩展包文件
  [root@python virtualenvs]# find / -name virtualenvwrapper.sh
  /usr/local/python3/bin/virtualenvwrapper.sh
  
  #配置环境变量
  [root@python virtualenvs]# vim /etc/profile
  [root@python virtualenvs]# tail -n 4 /etc/profile
  export WORKON_HOME=/virtualenvs
  export VIRTUALENVWRAPPER_PYTHON=/usr/bin/python3 
  source /usr/local/python3/bin/virtualenvwrapper.sh
  
  

• 执行环境文件，重新加载文件，使配置配置文件生效

  [root@python virtualenvs]# source /etc/profile
  virtualenvwrapper.user_scripts creating /virtualenvs/premkproject
  virtualenvwrapper.user_scripts creating /virtualenvs/postmkproject
  virtualenvwrapper.user_scripts creating /virtualenvs/initialize
  virtualenvwrapper.user_scripts creating /virtualenvs/premkvirtualenv
  virtualenvwrapper.user_scripts creating /virtualenvs/postmkvirtualenv
  virtualenvwrapper.user_scripts creating /virtualenvs/prermvirtualenv
  virtualenvwrapper.user_scripts creating /virtualenvs/postrmvirtualenv
  virtualenvwrapper.user_scripts creating /virtualenvs/predeactivate
  virtualenvwrapper.user_scripts creating /virtualenvs/postdeactivate
  virtualenvwrapper.user_scripts creating /virtualenvs/preactivate
  virtualenvwrapper.user_scripts creating /virtualenvs/postactivate
  virtualenvwrapper.user_scripts creating /virtualenvs/get_env_details
  

3. 创建python3虚拟环境的命令如下

• 创建虚拟环境，mkvirtualenv “虚拟环境名称”

  • 创建命令：

    mkvirtualenv 环境名称   
    

• 执行创建虚拟环境命令

  [root@python virtualenvs]# mkvirtualenv  python_3.8_base
  which: no virtualenv in (/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/root/bin)
  ERROR: virtualenvwrapper could not find virtualenv in your path
  
  #提示报错
  我们需要链接一下virtualenv
  [root@python virtualenvs]# ln -s /usr/local/python3/bin/virtualenv /usr/bin/virtualenv
  
  

• 重新执行创建虚拟环境命令

  root@python virtualenvs]# mkvirtualenv  python_3.8_base
  created virtual environment CPython3.7.4.final.0-64 in 969ms
    creator CPython3Posix(dest=/virtualenvs/python_3.8_base, clear=False, global=False)
    seeder FromAppData(download=False, pip=bundle, setuptools=bundle, wheel=bundle, via=copy, app_data_dir=/root/.local/share/virtualenv)
      added seed packages: pip==20.1.1, setuptools==49.2.0, wheel==0.34.2
    activators BashActivator,CShellActivator,FishActivator,PowerShellActivator,PythonActivator,XonshActivator
  virtualenvwrapper.user_scripts creating /virtualenvs/python_3.8_base/bin/predeactivate
  virtualenvwrapper.user_scripts creating /virtualenvs/python_3.8_base/bin/postdeactivate
  virtualenvwrapper.user_scripts creating /virtualenvs/python_3.8_base/bin/preactivate
  virtualenvwrapper.user_scripts creating /virtualenvs/python_3.8_base/bin/postactivate
  virtualenvwrapper.user_scripts creating /virtualenvs/python_3.8_base/bin/get_env_details
  

• 切换虚拟环境：使用"workon 虚拟环境名称" 切换虚拟环境

  • 命令示例：

    (Flask_cmdb)   [root@python virtualenvs]# workon python_3.8_base   
    (python_3.8_base)  [root@python virtualenvs]# 
    

• 退出虚拟环境：使用 “deactivate”命令退出虚拟环境

  • 命令示例

    (python_3.8_base)   [root@python virtualenvs]# deactivate   
    

• 删除虚拟环境：使用“rmvirtualenv 虚拟环境名称”

  • 命令示例：

    [root@python   virtualenvs]# rmvirtualenv python_3.8_base   Removing   python_3.8_base...  
    

• 改为阿里云的pip库

  [root@python virtualenvs]# mkdir -p ~/.pip
  [root@python virtualenvs]# vim ~/.pip/pip.conf
  [root@python virtualenvs]# cat ~/.pip/pip.conf 
  [global]
  index-url = http://mirrors.aliyun.com/pypi/simple/
  
  [install]
  trusted-host=mirrors.aliyun.com