From 11c4045ea9d20fb9a4ef5e7d86eb751a8c3a2bdd Mon Sep 17 00:00:00 2001
From: mozillazg <mozillazg101@gmail.com>
Date: Sun, 9 Jun 2024 18:04:29 +0800
Subject: [PATCH] add new flag `-D`: Print the list of the network interfaces
 available on the system

---
 README.md   |  3 +--
 cmd/list.go | 15 ++++++++++++---
 cmd/root.go |  2 +-
 3 files changed, 14 insertions(+), 6 deletions(-)

diff --git a/README.md b/README.md
index ad7c1f7b..b2f4426e 100644
--- a/README.md
+++ b/README.md
@@ -144,7 +144,7 @@ Flags:
 | --print                                           | ✅       | ✅                        |
 | -c *count*                                        | ✅       | ✅                        |
 | -Q *direction*, --direction=*direction*           | ✅       | ✅                        |
-| --list-interfaces                                 | ✅       | ✅                        |
+| -D, --list-interfaces                             | ✅       | ✅                        |
 | -A                                                | ✅       |                          |
 | -B *bufer_size*, --buffer-size=*buffer_size*      | ✅       |                          |
 | --count                                           | ✅       | ✅                       |
@@ -152,7 +152,6 @@ Flags:
 | -d                                                | ✅       |                          |
 | -dd                                               | ✅       |                          |
 | -ddd                                              | ✅       |                          |
-| -D                                                | ✅       |                          |
 | -e                                                | ✅       |                          |
 | -f                                                | ✅       | ⛔                        |
 | -F *file*                                         | ✅       |                          |
diff --git a/cmd/list.go b/cmd/list.go
index bad4412a..62582ace 100644
--- a/cmd/list.go
+++ b/cmd/list.go
@@ -2,9 +2,10 @@ package cmd
 
 import (
 	"fmt"
-	"github.com/mozillazg/ptcpdump/internal/dev"
 	"sort"
 	"strings"
+
+	"github.com/mozillazg/ptcpdump/internal/dev"
 )
 
 func listInterfaces() error {
@@ -12,11 +13,19 @@ func listInterfaces() error {
 	if err != nil {
 		return err
 	}
-	outputs := []string{}
+	var interfaces []dev.Device
 	for _, d := range devices {
+		interfaces = append(interfaces, d)
+	}
+	sort.Slice(interfaces, func(i, j int) bool {
+		return interfaces[i].Ifindex < interfaces[j].Ifindex
+	})
+
+	outputs := []string{}
+	for _, d := range interfaces {
 		outputs = append(outputs, fmt.Sprintf("%d.%s", d.Ifindex, d.Name))
 	}
-	sort.Strings(outputs)
+
 	fmt.Printf("%s\n", strings.Join(outputs, "\n"))
 	return nil
 }
diff --git a/cmd/root.go b/cmd/root.go
index 76c83fd3..c20b9205 100644
--- a/cmd/root.go
+++ b/cmd/root.go
@@ -51,7 +51,7 @@ func init() {
 	rootCmd.Flags().StringVar(&opts.comm, "pname", "", "Filter by process name (only TCP and UDP packets are supported)")
 	rootCmd.Flags().BoolVarP(&opts.followForks, "follow-forks", "f", false,
 		"Trace child processes as they are created by currently traced processes when filter by process")
-	rootCmd.Flags().BoolVar(&opts.listInterfaces, "list-interfaces", false,
+	rootCmd.Flags().BoolVarP(&opts.listInterfaces, "list-interfaces", "D", false,
 		"Print the list of the network interfaces available on the system")
 	rootCmd.Flags().BoolVar(&opts.version, "version", false,
 		"Print the ptcpdump and libpcap version strings and exit")