Scheduled Tasks
Cron
-
To add a cron job, simply add it to your crontab file by typing
crontabin a shell -
To see an example of a crontab, you can view
/etc/crontab -
Example cronjob structure:
# 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 17 * * * * root cd / && run-parts --report /etc/cron.hourly 25 6 * * * root test -x /usr/sbin/anacron || ( cd / && run-parts --report /etc/cron.daily ) 47 6 * * 7 root test -x /usr/sbin/anacron || ( cd / && run-parts --report /etc/cron.weekly ) 52 6 1 * * root test -x /usr/sbin/anacron || ( cd / && run-parts --report /etc/cron.monthly ) # -
Each user can have their own crontab file. These files are usually stored in
/var/spool/cron/crontabs -
To edit and install a crontab, run
crontab -e -
To list your crontabs, run
crontab -l -
To remove a crontab, you can run
crontab -r -
The
/etc/crontabfile is the system-wide crontab.