portrange.go

package main

import (
	"net"
	"sort"
	"log"
	"strconv"
)

func main() {
	ports := make([]int, 0)
	for i:=0; i<20000;  i++ {
		l, err := net.Listen("tcp", ":0")
		if err != nil {
			log.Fatal(err)
		}
		_, _port, err := net.SplitHostPort(l.Addr().String())
		if err != nil {
			log.Fatal(err)
		}
		port, _ := strconv.Atoi(_port)
		ports = append(ports, port)
		l.Close()
	}
	sort.Ints(ports)
	for _, port := range ports {
		log.Println(port)
	}
}