不用再看了:

0 3 * * * /usr/bin/env bash -c 'cd /home/user/project && source /home/user/project/env/bin/activate && ./manage.py command arg' > /dev/null 2>&1

通用的方法:

* * * * * /usr/bin/env bash -c 'YOUR_COMMAND_HERE' > /dev/null 2>&1

这样做的好处是您不需要将crontab的SHELL变量从sh更改为bash

如果你和我一样是MacOS用户，你可以在/var/mail/{username}文件中查看crontab错误信息。像这样

tail /var/mail/{username}

如果出现“操作不允许”错误，也许你必须将cron添加到全磁盘访问应用程序(安全和隐私>隐私>全磁盘访问应用程序/execs)。

点击+按钮，转到/usr/sbin，双击cron文件。 然后它将修复“不允许”错误。详细步骤

这是我的代码:

0 19 * * * cd /Users/user/Desktop/Project && source /Users/user/Desktop/Project/venv/bin/activate && python command arg

我也有同样的问题:

我写了一个自定义的django命令来检查geodjango多边形内部的geodjango位置坐标，并且在自动化任务运行时遇到了麻烦，然而使用crontab这个命令对我来说是有效的:

* * * * * ./home/project/locations/locations.sh >> /var/log/locations.log 2>&1

我很抱歉第n个答案，但我检查了答案，确实有更简单和整洁的答案。

长话短说

在你的cron中使用venv的python二进制文件:

0 3 * * * /home/user/project/env/bin/python /home/user/project/manage.py 

很长的故事

We activate the virtual environment when we want to set the current shell with the python config of that specific virtual environment(that is binaries and modules of that). It is relevant to work with the current shell : execute multiple python commands on the current shell without the need to reference the full python path of the venv. In the frame of a cron or even a bash, which value to activate the environment ? Besides I read in some answers some references to bash rather than sh or still to define a wrapper to call the Python code. But why the hell should we bother with these ?

重复一遍，照做就好:

0 3 * * * /home/user/project/env/bin/python /home/user/project/manage.py 

文件证实:

你不需要特别激活一个环境;激活 只需将虚拟环境的二进制目录前置到您的路径， 这样" python "就会调用虚拟环境的python解释器 您可以运行已安装的脚本，而不必使用它们的全部 路径。但是，在虚拟环境中安装的所有脚本都应该 在不激活它的情况下也可以运行，并使用虚拟机运行 环境的Python自动。

在使用virtualenv时，运行python cron作业的唯一正确方法是激活环境，然后执行环境的python来运行代码。

一种方法是在你的python脚本中使用virtualenv的activate_this，参见:http://virtualenv.readthedocs.org/en/latest/userguide.html#using-virtualenv-without-bin-python

另一种解决方案是回显完整的命令，包括激活环境并将其管道到/bin/bash.考虑一下你的/etc/crontab:

***** root echo 'source /env/bin/activate; python /your/script' | /bin/bash

我也遇到过同样的问题，并花了很多时间去解决它。 这里没有一个解决方案对我有帮助，所以我分享了对我有用的方法:

在项目目录中打开一个新文件“pick_name.sh”。 在"pick_name.sh"文件中，写入并保存以下代码行:

#!/bin/bash
source /YOUR_VIRTUAL_ENV_PATH/bin/activate
export PYTHONPATH="${PYTHONPATH}:/PATH_TO_CUSTOM_MODULE_YOU_CREATED**OPTIONAL**"
export PYTHONPATH="${PYTHONPATH}:/PATH_TO_ANOTHER_CUSTOM_MODULE_YOU_CREATED**OPTIONAL**"
cd /PATH_TO_DIR_STORING_FILE_NAME.PY
python file_name.py

转到/var/spool/cron/crontabs(或到您的cron管理文件所在的位置)并打开“根”文件。 将这些行添加到crontab文件夹中的根文件中:

# m h  dom mon dow   command
* * * * * /PATH_TO_DIR_WHERE_PICK_NAME.SH_SITS/pick_name.sh >> /YOUR_PROJECT_DIR/cron_output.txt 2>&1

注:

This command (section 4.) will run the "pick_name.sh" file. In this example it runs every minute, so make sure you change it according to your needs. It writes all logs to a log file called "cron_ouput". No need to create the file before, it will be created automatically. Make sure to replace all paths (I wrote them in capital letters) to your paths. You can change file names, if so, make sure to change it in all appearances in my instructions to avoid errors. If you want to add another py file to run by cron, you need to add it to the "pick_nam.sh" file* not to the cron. Simply duplicate section 2. lines in the "pick_nam.sh" but without the "#!/bin/bash" part. Then, every time the cron will run "pick_name.sh" it will run all the files you specified inside of it. Make sure to restart cron after changes, it could have saved me a lot of debugging time, use this command:

systemctl restart cron