Crontab format

Crontab examples

*****/path/to/command
12345 6 

1Minute of hour0-59
2Hour of day0-23
3Day of month1-31
4Month of year1-12
5Day of week0-6 (0=Sunday)
6Command to run
/5 * * * * /usr/bin/mrtg /data/mrtg/172.25.0.1.cfg --logging /var/log/mrtg.log
2 11,15 * * * /data/scripts/portprobe-0.5.pl

*/5 means run every 5 minutes
2 11,15 means run 11:02 and 15:02 every day

/
Meaning of *
1Do job every minute, 60 times per hour
2Do job every hour, 24 times per day
3Ignore this field and use field 5
4Do job every month, 12 times per year
5Ignore this field and use field 3
Asterisk in both field 3 & 5 means job is run every day