What are you trying to accomplish with this? If you are trying to replace multiple cursors, the approach would be very different. What I'd do is record a macro

What are you trying to accomplish with this? If you are trying to replace multiple cursors, the approach would be very different. What I'd do is record a macro for the edit on one line into q, and then apply it to all relevant lines with a regex, e.g. g/regex/norm @q