The forward slash (/) constrains an attribute to a starting point and an interval. It is used to specify every N seconds, minutes, or hours within the minute, hour or day. For an expression of the form x/y, x represents the starting point and y represents the interval. The wildcard character may be used in the x position of an interval, and is equivalent to setting x to 0.
Intervals may only be set for second, minute, and hour attributes.
The following expression represents every 10 minutes within the hour:
It is equivalent to:
The following expression represents every two hours starting at noon: