glog_file.go
func shortHostname(hostname string) string {
	if i := strings.Index(hostname, "."); i >= 0 {
		return hostname[:i]
	}
	return hostname
}
func shortHostname(hostname string) string {
	if i := strings.Index(hostname, "."); i >= 0 {
		return hostname[:i]
	}
	return hostname
}
// shortHostname returns its argument, truncating at the first period.
// For instance, given "www.google.com" it returns "www".