从Django和Python执行命令行脚本

我正在构建一个Django管理命令,它使用paulhammond的webkit2png脚本创建网站截图( http://www.paulhammond.org/webkit2png/ )并将它们存储到我的数据库中。

对于这个命令,我使用“subprocess”中的“call”命令。如何在特定目录中执行此命令(在本例中是temp/under-django project)?我当前的代码如下所示,但找不到要执行的脚本,该脚本存储在我的virtualenv site packages文件夹中:

import os

from django.core.management.base import NoArgsCommand
from django.conf import settings
from subprocess import call

# Models
from reviews.models import Shop

class Command(NoArgsCommand):
    def handle_noargs(self, **options):
        # Shops
        shops = Shop.objects.all()

        path = os.path.join(settings.SITE_ROOT, '../env/lib/python2.6/site-packages')

        for shop in shops:
            print shop
            command = "cd temp; python %s/webkit2png.py -F %s" % (path, shop.url)
            call([command])

            # Read the screenshot file and insert to model's ImageField