I can't execute command inside vim but it can be executed in shell?
Question: I use vim, mac os x, virtualenv and zsh to develop python.

But i found a quite strange thing that, After i using virtualenv to create a
environment and install a python package with `pip install fabric` and execute
`fab` in command line. It works well.  
Then i open vim and execute `fab` with `:!fab`, it give me following error:

    
    
    Traceback (most recent call last):                                                  │ * Restarting with reloader
      File "/usr/local/bin/fab", line 5, in <module>                                    │ * Detected change in '/Users/ccheng/workspace/rms-rest/rms/account.py', reloading
        from pkg_resources import load_entry_point                                      │ * Restarting with reloader
      File "build/bdist.macosx-10.9-intel/egg/pkg_resources.py", line 2793, in <module> │ * Detected change in '/Users/ccheng/workspace/rms-rest/rms/account.py', reloading
                                                                                        │ * Restarting with reloader
      File "build/bdist.macosx-10.9-intel/egg/pkg_resources.py", line 673, in require   │ * Detected change in '/Users/ccheng/workspace/rms-rest/rms/rms.py', reloading
        def subscribe(self, callback):                                                  │ * Restarting with reloader
      File "build/bdist.macosx-10.9-intel/egg/pkg_resources.py", line 576, in resolve   │ * Detected change in '/Users/ccheng/workspace/rms-rest/rms/rms.py', reloading
        plugin_env, full_env=None, installer=None, fallback=True                        │ * Restarting with reloader
    pkg_resources.DistributionNotFound: Fabric==1.8.0                                   │ * Detected change in 'run.py', reloading
                                                                                        │ * Restarting with reloader
    shell returned 1   
    

I think it was caused by when i open vim, some `python path` variable has been
reset, so i can't find the packages installed in virtualenv.


Answer: I solve the issue through set a default shell in terminal configuration. I
don't know what is different between this and setting default shell using
'chsh', but it works. Thanks everyone.

