cron not executing?

Question

I have the following cron tab installed:

crontab -l
# m h  dom mon dow   command
*/10 * * * * "echo" >> /tmp/cron.log

The server is at rackspace, it's a cloud server:

Linux myserver #8 SMP Mon Sep 20 15:54:33 UTC 2010 x86_64 GNU/Linux
Ubuntu 10.04 LTS

When I added this entry to the crontab using crontab -e I got the following message when I saved it:

crontab: installing new crontab

But it's not being executed, what is missing?

Echo should not be quoted there. Also you might want to provide the full path. Cron's $PATH environment variable is often very restricted.
You might also find it useful to run date instead of echo. This will give you a series of timestamps in your log file instead of sending a blank line!
@Caleb: It works, it just creates a file with a blank line each time it runs.

Iain · Answer 1 · 2011-04-23 16:07:16Z

Things to check

Is cron running ?

$ ps aux | grep cron | grep -v grep
root      1015  0.0  0.0  21076  1020 ?        Ss   14:36   0:00 cron
$

If cron isn't running you can start it with

sudo service cron start

If cron is running then have a look in /var/log/syslog for any related messages

$ sudo grep CRON /var/log/syslog 
...
Apr 23 16:50:01 iain-10-04 CRON[5193]: (iain) CMD ("echo" >>/tmp/cron.log)
$

Any output from the cron job will also be mailed to the user who's job it is. Check the mail on the system.

1 Answer