Function mapper

lib/transform/transform.go:395–402

(s string, command string)

}

func mapper(s string, command string) (string, error) {
	out, err := exec.Command(command, s).CombinedOutput()
	if err != nil {
		out = bytes.TrimSpace(out)
		return s, fmt.Errorf("%s: error running command %q: %v", out, command+" "+s, err)
	}
	return string(bytes.TrimSpace(out)), nil
}