There are no corn jobs, there are however Korn shell scripts, and there are also cron jobs, which are scheduled tasks.
Code:
#!/bin/ksh #specify the Korn shell
cd log_directory
find ./ -mtime +10 -exec rm {} \;
Add the following line to the cron file for whichever user is going to run the job.
Code:
0 23 * * * /home/user/delete_log_script >/home/user/delete_log_script.log 2>&1
This line will run your script at 11pm every day and create a log of the script's activity.
You really need to read the following:
man cron
man crontabs