安装virtualenvwrapper
这里使用pip3进行安装即可
sudo pip3 install virtualenvwrapper
设置virtualenvwrapper的运行环境变量
编辑~/.bashrc,加入以下几行
VIRTUALENVWRAPPER_PYTHON=/usr/bin/python3 
export WORKON_HOME='~/.virtualenvs'
source /usr/local/bin/virtualenvwrapper.sh
使环境变量马上生效:
source ~/.bashrc
virtualenvwrapper使用
mkvirtualenv 新建虚拟环境
mkvirtualenv env1
建立后可以看到终端会以env1开头
(env1) [ning@localhost]$
再建立一个env2
mkvirtualenv env2
workon 启动/切换虚拟环境
workon env1
deactivate 离开虚拟环境
deactivate
rmvirtualenv 删除虚拟环境
rmvirtualenv env2
virtualenvwrapper help 查看virtualenvwrapper使用帮助
virtualenvwrapper is a set of extensions to Ian Bicking's virtualenv
tool.  The extensions include wrappers for creating and deleting
virtual environments and otherwise managing your development workflow,
making it easier to work on more than one project at a time without
introducing conflicts in their dependencies.
For more information please refer to the documentation:
    http://virtualenvwrapper.readthedocs.org/en/latest/command_ref.html
Commands available:
  add2virtualenv: add directory to the import path
  allvirtualenv: run a command in all virtualenvs
  cdproject: change directory to the active project
  cdsitepackages: change to the site-packages directory
  cdvirtualenv: change to the $VIRTUAL_ENV directory
  cpvirtualenv: duplicate the named virtualenv to make a new one
  lssitepackages: list contents of the site-packages directory
  lsvirtualenv: list virtualenvs
  mkproject: create a new project directory and its associated virtualenv
  mktmpenv: create a temporary virtualenv
  mkvirtualenv: Create a new virtualenv in $WORKON_HOME
  rmvirtualenv: Remove a virtualenv
  setvirtualenvproject: associate a project directory with a virtualenv
  showvirtualenv: show details of a single virtualenv
  toggleglobalsitepackages: turn access to global site-packages on/off
  virtualenvwrapper: show this help message
  wipeenv: remove all packages installed in the current virtualenv
  workon: list or change working virtualenvs
virtualenv –help 帮助
Usage: virtualenv [OPTIONS] DEST_DIR
Options:
  --version             show program's version number and exit
  -h, --help            show this help message and exit
  -v, --verbose         Increase verbosity.
  -q, --quiet           Decrease verbosity.
  -p PYTHON_EXE, --python=PYTHON_EXE
                        The Python interpreter to use, e.g.,
                        --python=python2.5 will use the python2.5 interpreter
                        to create the new environment.  The default is the
                        interpreter that virtualenv was installed with
                        (/usr/bin/python3)
  --clear               Clear out the non-root install and start from scratch.
  --no-site-packages    DEPRECATED. Retained only for backward compatibility.
                        Not having access to global site-packages is now the
                        default behavior.
  --system-site-packages
                        Give the virtual environment access to the global
                        site-packages.
  --always-copy         Always copy files rather than symlinking.
  --unzip-setuptools    Unzip Setuptools when installing it.
  --relocatable         Make an EXISTING virtualenv environment relocatable.
                        This fixes up scripts and makes all .pth files
                        relative.
  --no-setuptools       Do not install setuptools in the new virtualenv.
  --no-pip              Do not install pip in the new virtualenv.
  --no-wheel            Do not install wheel in the new virtualenv.
  --extra-search-dir=DIR
                        Directory to look for setuptools/pip distributions in.
                        This option can be used multiple times.
  --download            Download preinstalled packages from PyPI.
  --no-download, --never-download
                        Do not download preinstalled packages from PyPI.
  --prompt=PROMPT       Provides an alternative prompt prefix for this
                        environment.
  --setuptools          DEPRECATED. Retained only for backward compatibility.
                        This option has no effect.
  --distribute          DEPRECATED. Retained only for backward compatibility.
                        This option has no effect.