<s>[INST] Cron and virtualenv I am trying to run a Django management command from cron. I am using virtualenv to keep my project sandboxed.
I have seen examples here and elsewhere that show running management commands from within virtualenv's like:
0 3 * * * source /home/user/project/env/bin/activate && /home/user/project/manage.py command arg

However, even though syslog shows an entry when the task should have started, this task never actually runs (the log file for the script is empty). If I run the line manually from the shell, it works as expected. 
The only way I can currently get the command to run via cron, is to break the commands up and put them in a dumb bash wrapper script:
#!/bin/sh
source /home/user/project/env/bin/activate
cd /home/user/project/
./manage.py command arg

Please enlighten me what the difference is. What am I missing?
Thanks
EDIT:
ars came up with a working combination of commands:
0 3 * * * cd /home/user/project && /home/user/project/env/bin/python /home/user/project/manage.py command arg

At least in my case, invoking the activate script for the virtualenv did nothing. This works, so on with the show.
 [/INST] You should be able to do this by using the python in your virtual environment:
/home/my/virtual/bin/python /home/my/project/manage.py command arg

EDIT: If your django project isn't in the PYTHONPATH, then you'll need to switch to the right directory:
cd /home/my/project && /home/my/virtual/bin/python ...

You can also try to log the failure from cron:
cd /home/my/project && /home/my/virtual/bin/python /home/my/project/manage.py > /tmp/cronlog.txt 2>&1

Another thing to try is to make the same change in your manage.py script at the very top:
#!/home/my/virtual/bin/python

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