陷入逻辑试图匹配模式？

Question

I am running a script based on exetime and exetime is saved in database in the format of following.

* * * * * *
| | | | | | 
| | | | | +-- Year              (range: 1900-3000)
| | | | +---- Day of the Week   (range: 1-7, 1 standing for Monday)
| | | +------ Month of the Year (range: 1-12)
| | +-------- Day of the Month  (range: 1-31)
| +---------- Hour              (range: 0-23)
+------------ Minute            (range: 0-59)

Now I need to check exetime with current

M.H.DofM.MofY.DofW.Y

each field can have two possibilies , it could be respective field or it could be a "*" . what will be the best way two check this pattern with all combination with each field having 2 possibilities.

Answer 1

Here is the regexp I think :

([0-5]?[0-9]|\*)\.([0-1]?[0-9]|2[0-3]|\*)\.([1-2]?[0-9]|3[0-1]|\*)\.([0-9]|1[0-2]|\*)\.([1-7]|\*)\.(19[0-9][0-9]|2[0-9]{3}|3000|\*)

Let's explain this one part by part, the | equals to the "and" of my explain; all the part are separate by \. which is the "."

([0-5]?[0-9]|\*) 

Will match all number from 0 to 59 or * This ( as the others ) will allow you to use 00

([0-1]?[0-9]|2[0-3]|\*)

Will match all number from 0 to 19 and from 20 to 23 or *

([1-2]?[0-9]|3[0-1]|\*)

Will match all number from 0 to 29 and from 30 to 31 or *

([0-9]|1[0-2]|\*)

Easy one; from 0 to 9 or from 10 to 12 or *

([1-7]|\*)

Match 1 to 7 or *

(19[0-9][0-9]|2[0-9]{3}|3000|\*)

Match from 1900 to 1999 and from 2000 to 2999 and 3000 or *

Here is an example : https://regex101.com/r/Orlp3o/2

I let you test some more ;)

Well, I edit my answer in order to add @Mark Baker one, https://github.com/mtdowling/cron-expression

Now you can choose which one you want to use ;)