If you have ever tried to create a cronjob on one of the tardis machines, you may have noticed that you are lacking the necessary permissions.

There is one exception to this rule: here. Every user can create cronjobs on this machine just as he likes. The reason for imposing this restriction is to simplify the debugging of cronjob problems, as it will be clear that they occur on this particular machine. Furthermore it helps us as admins to clean up cronjobs when a user is archived.

Cron Hints

A job that is started via cron is running under special conditions, so you must take the following into consideration:

Sample Cron-Script

mkdir -p ~/bin
cat <<SCRIPT >~/bin/
# shell scripts should be written in /bin/sh
# see also
# uncomment the following line to get a running output of what
# the script does
#set -x
# set an absolut path to be sure that the script works everywhere
export PATH
# show me who is working on tardis-a15. if no one is working there be quiet.
rwho | grep tardis-a15
# end of script
chmod 755 ~/bin/

The commands above, when entered into you shell will create now run crontab -e to add it to your crontab. If you want the script to run every hour at 15 minutes past the hour it would look like this:

15 * * * * $HOME/bin/

With crontab -l you can check if the cronjob has been properly accepted.

And ...

Learn more about cron with man cron, man 1 crontab and man 5 crontab.


Services/Cronjob (last edited 2013-07-17 12:26:53 by bonaccos)