Command for the # cron on SERVER

With this command you will see the user's cron tasks you entered in via SSH:

crontab -l

Con este comando podrás ver las tareas cron de un usuario específico, for example:

crontab -u mailman -l

With this command you will see all the users who have created a cron job:

ls -l /var/spool/cron

SOURCE: http://www.comunidadhosting.com/asuntos-tecnicos/15096-comando-para-conocer-el-de-crons-en-el-server.html