CRON - cause I always forget
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The cron format.
# .---------------- 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
# | | | | |
# * * * * * [command to be executed\]
I addition to the above syntax you can use the following, more easily remembered, special words.
@yearly, @monthly, @daily, @hourly, @reboot (at startup)
These are however not available in every cron daemon.
Every minute
* * * * * /miff/moff/meff.sh
Every five minutes
*/5 * * * * /miff/moff/meff.sh
Every two minutes the first half hour of every hour
0-30/2 * * * * /miff/moff/meff.sh
More examples can be found here ;).