Rename cmd -> examples

examples/mcping/README.md

@@ -0,0 +1,17 @@
+# mcping
+
+Ping tool for Minecraft: Java Edition.
+Just for example. Not recommended for daily use. Use [github.com/go-mc/mcping](github.com/go-mc/mcping) instead, which including SRV parse.
+
+适用于Minecraft: Java Edition的ping工具。
+只起示例作用，日常使用建议使用完整版[github.com/go-mc/mcping](github.com/go-mc/mcping)，包含SRV解析等功能。
+
+Install with go tools:  
+    ```go get -u github.com/Tnze/go-mc/cmd/mcping```
+    `$GOPATH/bin` should in your `$PATH`.
+
+Install with Homebrew:  
+    ```brew tap Tnze/tap && brew install mcping```
+
+Useage:  
+    ```mcping <hostname>[:port]```

examples/mcping/mcping.go

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+// Usage: go run examples/ping/ping.go localhost
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+	"os"
+	"strings"
+
+	"github.com/Tnze/go-mc/bot"
+	"github.com/Tnze/go-mc/chat"
+	"github.com/google/uuid"
+)
+
+type status struct {
+	Description chat.Message
+	Players     struct {
+		Max    int
+		Online int
+		Sample []struct {
+			ID   uuid.UUID
+			Name string
+		}
+	}
+	Version struct {
+		Name     string
+		Protocol int
+	}
+	//favicon ignored
+}
+
+func main() {
+	addr := getAddr()
+	fmt.Printf("MCPING (%s):\n", addr)
+	resp, delay, err := bot.PingAndList(addr)
+	if err != nil {
+		fmt.Printf("ping and list server fail: %v", err)
+		os.Exit(1)
+	}
+
+	var s status
+	err = json.Unmarshal(resp, &s)
+	if err != nil {
+		fmt.Print("unmarshal resp fail:", err)
+		os.Exit(1)
+	}
+
+	fmt.Print(s)
+	fmt.Println("Delay:", delay)
+}
+
+func getAddr() string {
+	const usage = "Usage: mcping <hostname>[:port]"
+	if len(os.Args) < 2 {
+		fmt.Println("no host name.", usage)
+		os.Exit(1)
+	}
+
+	return os.Args[1]
+}
+
+func (s status) String() string {
+	var sb strings.Builder
+	fmt.Fprintln(&sb, "Server:", s.Version.Name)
+	fmt.Fprintln(&sb, "Protocol:", s.Version.Protocol)
+	fmt.Fprintln(&sb, "Description:", s.Description)
+	fmt.Fprintf(&sb, "Players: %d/%d\n", s.Players.Online, s.Players.Max)
+	for _, v := range s.Players.Sample {
+		fmt.Fprintf(&sb, "- [%s] %v\n", v.Name, v.ID)
+	}
+	return sb.String()
+}