+ <p>
+ Unlike <file>crontab</file> files described in the IEEE Std
+ 1003.1-2008 (POSIX.1) available from
+ <url id="http://www.opengroup.org/onlinepubs/9699919799/"
+ name="The Open Group">, the files in
+ <file>/etc/cron.d</file> and the file
+ <file>/etc/crontab</file> have seven fields; namely:
+ <enumlist>
+ <item>Minute [0,59]</item>
+ <item>Hour [0,23]</item>
+ <item>Day of the month [1,31]</item>
+ <item>Month of the year [1,12]</item>
+ <item>Day of the week ([0,6] with 0=Sunday)</item>
+ <item>Username</item>
+ <item>Command to be run</item>
+ </enumlist>
+ Ranges of numbers are allowed. Ranges are two numbers
+ separated with a hyphen. The specified range is inclusive.
+ Lists are allowed. A list is a set of numbers (or ranges)
+ separated by commas. Step values can be used in conjunction
+ with ranges.
+ </p>