Python PIP 声称已安装包,但我使用时找不到包

Python PIP claims that a package is installed but whet I use package it is not found

我一直在尝试设置合适的虚拟环境。我遇到了 this。但是我还是无法使用这个包:

yathi@DarkWater-U:~$ pip install virtualenvwrapper
Requirement already satisfied (use --upgrade to upgrade): virtualenvwrapper in /usr/local/lib/python2.7/dist-packages
Cleaning up...
yathi@DarkWater-U:~$ workon
workon: command not found
yathi@DarkWater-U:~$ mkvirtualenv
mkvirtualenv: command not found

通过谷歌搜索,我发现问题可能是因为我使用了 sudo pip install 而不是 pip install。但是现在我不知道如何更正问题并正确安装软件包。

请阅读documentation:

$ pip install virtualenvwrapper
...
$ export WORKON_HOME=~/Envs
$ mkdir -p $WORKON_HOME
$ source /usr/local/bin/virtualenvwrapper.sh
$ mkvirtualenv env1