package main
import (
"regexp"
"fmt"
)
func main() {
var re = regexp.MustCompile(`(?m)(?=.{30})(.{1,29})\s`)
var str = `the quick brown fox jumped over the lazy dog near the bank of the river by 123 4567 8901234 567 89012 3456 789abc 012345 67890`
var substitution = "$1, "
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/