A much easier option is to use labels and perl to swap comment items around in the nginx.conf file. #PLABEL #development line....; production line....; if readln eq '^#PLABEL' then { swap 2 lines comment char; } else { write unchangedline; } Or something in that order. Posted at Nginx Forum: http://forum.nginx.org/read.php?2,256733,256734#msg-256734