CodeLiner is a toolbar in the Excel VBA Editor that allows you to add and remove code line numbers with one click. Code line numbers are important because they allow you to discover the exact location of an error or other condition. The Excel built-in function, Erl(), will not return a line number until code line numbers have been added to the VBA Project - that is where CodeLiner helps. Not only does it allow use of the Erl() function, but CodeLiner instantly cleans up code line numbers so that you will have a completely unobstructed view of your code. When ready to debug errors or deploy to production, you can use CodeLiner to toggle on the code line numbers again.