Need help with a sed script

Anders, I see your online, maybe you can answer this fairly quickly for me. I don't use sed very often, how do I shift the first 2 chars of every line to chars 5 & 6. In otherwords if I have lines like: 123456rest of line. I need it to be: 345612rest of line. Reading a tutorial, I think it is something like: sed -e 's@^\(?\)\(?\)\(?\)\(?\)\(?\)\(?\)@\3\4\5\6\1\2@' file I'm going off to try that now. PS: Any tool can be used, but I have 80,000 lines to modify in a single file, and sed is the only tool I know for the job. Thanks Greg -- Greg Freemyer The Norcross Group Forensics for the 21st Century -- Greg Freemyer The Norcross Group Forensics for the 21st Century