You have a couple of different problems here, the first is that you are reading SF into a scalar, $fmt_edi, when you evaluate a filehandle as a scalar, you only get one line at a time, so you will only get the first line of your input file processed. Second, the perlre documentation has a list of characters that are special when preceded by a backslash. The letter v is not in this list, which means that '\v' has the same meaning as 'v' and will replace all the lowercase letter v's with newlines. (perlre also indicates the 'vertical tabulator' character is \ck)