* IF you are using a distro such as Ubuntu 14.04 where first line of /etc/crontab is "m h dom mon dow user command" then if you want regular refresh of map then run
(otherwise first edit the script to fit your crontab then)
(otherwise first edit the script to fit your crontab then)
(if you are not using /var/www/html/minetest/chunkymapdata, edit chunkymap-cronjob script to use the correct folder, then)