Sign up ×
Ask Ubuntu is a question and answer site for Ubuntu users and developers. It's 100% free.

I have an sh file called with the contents:

echo "Cleaning memory"
sync; echo 3 > /proc/sys/vm/drop_caches
echo ""
free -m

echo ""

ps cax | grep java > /dev/null
if [ $? -eq 0 ]; then
  echo "== Server is already running =="
  echo "========== STARTING THE SERVER =========="

When I run it with sh it works perfectly. But I need it to run every 5 minutes, so I am using cron jobs. It needs to work as root/sudo so I did sudo -s, then crontab -e and wrote this in the file:

0,4,9,14,19,24,29,34,39,44,49,54 * * * * /bin/sh /home/<username>/

I had done some research, and I learned that the cron has different paths than the user, that is why I used those absolute paths, to make sure.

The cron job wasn't running the script every 5 minutes, as it was supposed to.

I also added

* * * * * /bin/echo "Testing123"

to test if cron was working at all, and nothing came up in the console.

How can I make the cron run the script every 5 minutes? I did research online, and tried the solutions, but couldn't make it to work for me. I did service cron start and it said it was already running. I also restarted the service. The permissions are set correctly, I gave all users read, write, and execute permissions just to make sure (I know the permissions are correct).

share|improve this question

2 Answers 2

up vote 2 down vote accepted

Regarding your test script -- crontab jobs are not connected to a physical console, so don't expect any output. Try

* * * * * /bin/touch /tmp/foo

... and see whether the /tmp/foo file gets updated. It should.

To get a script running every five minutes, there is a shortcut:

*/5 * * * * /bin/sh /whatever/script/

Furthermore, I would edit your script such that it logs its activity. For example,

# ...
echo `date '+%Y-%m-%d %H:%M:%S'` Starting server >> $LOGFILE

Alternatively, you can redirect the output from the crontab file directly:

*/5 * * * * /bin/sh /whatever/script/ >> /var/log/leoncleaner.log
share|improve this answer
Thanks, I've got it figured out now. I don't know what the problem was before, maybe it was working but I didn't know it. Also, is there a way to make it write the output in the console? – BaranCODE Jul 4 '13 at 12:15
Sort of. Redirect the output of the script to a log file ( Then open a console and type tail -f It will read the file and update the output when the file grows. – January Jul 4 '13 at 12:16
Oh, wait, it isn't fixed. I stopped the server, and waited for the cron job to restart it. In the logs I could see that when it noticed the server had stopped, it said "Starting the server", but it actually didn't. But when I run that script myself, and it said "Starting the server", it did. The script is working apparently, because it works when I run it, but only half works when it is run by cron – BaranCODE Jul 4 '13 at 12:28
OK, but that is another issue. Add the full path to – January Jul 4 '13 at 12:29
I changed sh with sh /home/<username>/ but the exact thing still happens – BaranCODE Jul 4 '13 at 12:33

Try running echo PATH=$PATH > path.tmp. Then add the contents of path.tmp to the beginning of your script. This will provide the same path you have interactively to the script.

You may want to add a bang path to beginning of your scrript. Something like #!/bin/bash should work.

Also make sure your script is executable. Run the command chmod +x Then test your script can be run as ./

Output of the script should be mailed to the user id of the crontab it is running. In the case of root, ensure you have an alias to a user id you are monitoring for mail in /etc/aliases. Generally, you don't want output from cron scripts unless something fails. Redirect output to a log if you need it.

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.