In Linux you can list the contents of a users crontab from root by issuing the below command:[root@server ~]#crontab -u username -l
How do you list crontabs for all of the users on your Linux server? The easiest way is to list the contents of /var/spool/cron which will provide you a list of all of the users that have cron entries. Then if you need the specific details of a users cron entries you can use the command above and replace username with the username in question to see the details.
Other places to look for cron specific tasks would be the below locations:
/etc/crontab – provides specific details for cron including what the hourly, daily, weekly, and yearly cron tasks
/etc/cron.hourly – directory with hourly cron tasks
/etc/cron.daily – directory with daily cron tasks
/etc/cron.weekly – directory with weekly cron tasks
/etc/cron.monthly – directory with monthly cron tasks