fabricのお役立ちコンテキストマネージャ ref: http://qiita.com/items/d848a7e0a6271baa722d

djscript.py

import fabric.api as api

with api.env_shell("PYTHONPATH=. DJANGO_SETTINGS_MODULE=settings.imagawa"):
    api.run("python dosomething.py")

enablevenv.py

import fabric.api as api

with api.prefix(". /home/www/bin/activate"):
    fabric.api.run("./manage.py syncdb")

fabpath.py

import fabric.api as api

with api.path("/usr/local/bin", behavior="prepend"):
    api.run("python -V")