Servers can automatically perform tasks that you would otherwise have to perform yourself, such as running scripts. On Linux servers, the cron utility is the preferred way to automate the running of scripts. For an introduction to Cron check-out our KB: How To: Automate Server Scripts With Cron

crontab -l

crontab -u username -l

Example with user testuser:

crontab -u testuser -l

First view all the daily cron jobs:

ls -la /etc/cron.daily/

Then view a specific daily cron job:

less /etc/cron.daily/filename

Example with filename logrotate:

less /etc/cron.daily/logrotate

First view all the hourly cron jobs:

ls -la /etc/cron.hourly/

Then view a specific hourly cron job:

less /etc/cron.hourly/filename

Example with filename 0anacron:

less /etc/cron.hourly/0anacron

First view all the weekly cron jobs:

ls -la /etc/cron.weekly/

Then view a specific weekly cron job:

less /etc/cron.weekly/filename

Example with filename weeklyexample:

less /etc/cron.weekly/weeklyexample

First view all the monthly cron jobs:

ls -la /etc/cron.monthly/

Then view a specific monthly cron job:

less /etc/cron.monthly/filename

Example with filename readahead-monthly.cron:

less /etc/cron.monthly/readahead-monthly.cron

less /etc/crontab

Example Result:

SHELL=/bin/bash
PATH=/sbin:/bin:/usr/sbin:/usr/bin
MAILTO=root
HOME=/
# For details see man 4 crontabs

# Example of job definition:
# .—————- minute (0 – 59)
# | .————- hour (0 – 23)
# | | .———- day of month (1 – 31)
# | | | .——- month (1 – 12) OR jan,feb,mar,apr …
# | | | | .—- day of week (0 – 6) (Sunday=0 or 7) OR sun,mon,tue,wed,thu,fri,sat
# | | | | |
# * * * * * user-name command to be executed

For more information check-out our KB: How To: Automate Server Scripts With Cron