This is what my crontab file looks like:
* * * * * root /usr/bin/python /root/test.py >> /root/classwatch.log 2>&1
This is what my python script looks like:
#!/usr/bin/python
print "hello"
The cronjob creates the log file. But it is empty. I am also pretty certain that the python file is not being executed.
Appreciate any help! I've been playing with it for past 4 hrs with no luck.
There are two ways to create a crontab -- per user or globally. For the global crontab (/etc/crontab) you specify the user, as per:
# m h dom mon dow user command
17 * * * * root cd / && run-parts --report /etc/cron.hourly
For user crontabs you don't, as per:
aj@wherever:~$ crontab -l
0 * * * * /home/aj/bin/update-foobar
To get a python script running via #! notation, you just make the script executable (chmod 755 /root/test.py), and invoke it directly, something like:
/root/test.py
If you don't want to do that, you can run it via the python interpretor by hand, like:
/usr/bin/python /root/test.py
This assumes whichever user you're running as (ie the user in /etc/crontab, or the user you're running crontab -e as) has permission to see the python script -- /root might be inaccessible to regular users, eg.
You can get a good idea of whether your script is being executed at all by adding:
import time
time.sleep(20) # pause for 20 seconds
and then checking with "top" or "ps aux" or "pstree" to see if python's actually running.
Updated...
Replace the contents with
* * * * * date >> /tmp/foo
Does this link help?
Delete the file it is supposed to create. Does it come back?
I thought each user had his own crontab file so the user on the line is suspsect.
DId someone play a joke on you and replace the python binary with a no op?
I have to think cron isn't working right since the echo doesn't work. Did you make sure to change the output directory to /tmp with the echo?
can you do an od (octal dump) of the file and see if maybe you put a control character or a tab into the cron file?
chmod 755 /root/test.py
and then
* * * * * /root/test.py >> /root/classwatch.log 2>&1
should work.
Have you tried putting the script someplace else (e.g. /usr/local/bin/)?
This works fine for me on my RHES 4 Linux box exactly as shown (NOTE: I removed the 'root' username in the crontab).
I suspect there's something wrong with the way you're installing your cron job, or the configuration of cron on your system. How are you installing this? Are you using crontab -e or some other method? Are you able to run any other cron jobs for root successfully?
It might be because of a job declared earlier failing due to syntax error. Can you paste your entire crontab? Your line looks good as far as I can see.
Try just sending stdout to the log file, instead of both stderr and stout:
/usr/bin/python /root/test.py > /root/classwatch.log
