I am just wondering why the cronjob in linux system doesn't work. I run the script it works fine, but if I add script to crontab it fails to run. (00 12 * * * /usr/local/scriptname 1>/dev/null 2>/dev/null), I double check the permission of script, it's correct. Does anybody have solutions?

Make sure to specify the full path for any commands in your script. EX: "/usr/sbin/useradd" instead of "usradd"

Make sure that the crond is running: ps ax |grep crond

Crond is running at deamon, I can also use "admin" login to run crontab, however if I use "root" to run crontab, it fails, don't know what's happen.(I use full path, and the script works fine if I run it from command line)

What is failing to work? Does the script itself not start or some commands in the script are failing to run? When you run it in a shell you'll normally have environment variables set. When you run it from the crontab you won't have all the same environment variables. So you'll either have to set them in the crontab file or in the script itself. Try making the script do something simple like /bin/date >> /dir/scriptdate or something else which you know will always work. Mik

take a look to the /var/log/cron and make sure the process is executed as per the schedule. If there is really an error in teh script, it should appear in your email.