>There is something I am trying to understand with a RegEx expression.
>
>Here is an expression: ([A-Za-z0-9-]{1,20})-([A-Za-z0-9]{1,12})
>
>That one allows alphanumeric characters from anywhere from the 1st to the 20th character. This includes as well a dash starting from position 2.
>
>This is the part I cannot understand. What in there is a representation that the dash is valid from position 2?


I don't think it does. The dash seems to be a valid character in the first grouping, and can therefore be in the first position, as in:

-a15a-a20
-1637-b2

Tested with: http://regexpal.com/
"Your friend in building RegEx pressions." :-)