package main
import (
"regexp"
"fmt"
)
func main() {
var re = regexp.MustCompile(`(?m)(?=^sudo:x:\d+:.*$)(.*):`)
var str = `sudo:x:27:foo,bar,baz
nosudo:x:27:foo,bar,baz`
var substitution = "\1<mychar>"
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/