Adding CRLF to file with no delimiters

I've got a flat file that I need to add a CRLF to after each 129 chars. This is so a Unix program can run against it, which needs/uses CRLF as a delimiter.  I've tried to use a derived column but since I'm adding 2 chars the next 129 char are off by two. I think i need to use a script task and just create a new file from the original and add the CRLF after each 129 chars. Any other ideas? I'm fairly new to SSIS. I'm using VS 2017