I want to apply css to all class that starts with for example \'abcd-\' but I don\'t want to apply that css to class with name for example \'abcd-dontapply\'. Can I do this?
As mentioned in your question:
Don't add whitespace unnecessarily. The whitespace just before the :not is significant, i.e. it changes the meaning of the selector.
a[class^="abcd"]:not(.abcd-dontapply) { /* define CSS here*/ }
You can find all attribute selectors specifications here.