Regex for product key

Question

I am trying to do a regex that will show all product keys with the value #####-#####-#####-#####-#####

this is the regular expression i have created

[A-Z0-9]{5}-[A-Z0-9]{5}-[A-Z0-9]{5}-[A-Z0-9]{5}-[A-Z0-9]{5}

for some reason it just isn't working.

Answer 1

You should anchor the pattern:

/\A[A-Z0-9]{5}-[A-Z0-9]{5}-[A-Z0-9]{5}-[A-Z0-9]{5}-[A-Z0-9]{5}\z/

Answer 2

In what language or system are you doing this? Not all of them accept the {n} repetition notation.

Answer 3

Which regex tool do you intend to use? grep, egrep, sed, perl, etc?

Also, you may want to allow lowercase letters:

Using egrep, and cygwin, this works: '^([A-Za-z0-9]{5}-){4}[A-Za-z0-9]{5}$'

But as Hyman points out, {} is not valid in every regex set (hence why I used egrep, not grep).