Do want to see if it is an integer or if it's a string that looks like an integer?

Since you've anchored the regex at the begging and at the end I'm going to assume that you're checking that the value is a positive integer.

Check if the value is a Positive Integer:

if ( $ref == int($ref) and $ref eq int($ref) and $ref > 0 )
{
    print "$ref is a positive int!\n"
}
[download]

I'll leave the negative test as an exercise for the reader.

update: added an additional test to prevent strings like 23EatAtJoes being considered a positive integer.

This method fails and is unwieldy with integers larger than 999999999999999 on my system. I suggest Using one of the more robust methods suggested in the thread.

--
Clayton aka "Tex"