package main
import (
"regexp"
"fmt"
)
func main() {
var re = regexp.MustCompile(`(?m)(?<!^)\b[0-9]{5,9}:`)
var str = `13371337:Bat,TH,Li-Met,Blub,9.5V,370mAHr,1/2_AA-Cell,50pcs,13351234:Radio - Antenna 2.4 GHz AB/C midi (10p),15642345:Board SMB - Some Magic Board,95653345:Board SMK 6 - Some Magic Knobs - Mod6,56735632:Control Unit Z65 - Mod9`
var substitution = "\n\g<0>"
fmt.Println(re.ReplaceAllString(str, substitution))
}
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Golang, please visit: https://golang.org/pkg/regexp/