feat: create commands_interfaces.go and add InterfacesCommand

Create separate file for interfaces command handling to improve code organization.
Add InterfacesCommand struct with ListInterfaces method that handles the
logic to list current system interfaces.

cmd/cli/commands_interfaces.go

@@ -0,0 +1,88 @@
+package cli
+
+import (
+	"fmt"
+	"net"
+
+	"github.com/spf13/cobra"
+)
+
+// InterfacesCommand handles interfaces-related operations
+type InterfacesCommand struct{}
+
+// NewInterfacesCommand creates a new interfaces command handler
+func NewInterfacesCommand() (*InterfacesCommand, error) {
+	return &InterfacesCommand{}, nil
+}
+
+// ListInterfaces lists all network interfaces
+func (ic *InterfacesCommand) ListInterfaces(cmd *cobra.Command, args []string) error {
+	withEachPhysicalInterfaces("", "Interface list", func(i *net.Interface) error {
+		fmt.Printf("Index : %d\n", i.Index)
+		fmt.Printf("Name  : %s\n", i.Name)
+		var status string
+		if i.Flags&net.FlagUp != 0 {
+			status = "Up"
+		} else {
+			status = "Down"
+		}
+		fmt.Printf("Status: %s\n", status)
+		addrs, _ := i.Addrs()
+		for i, ipaddr := range addrs {
+			if i == 0 {
+				fmt.Printf("Addrs : %v\n", ipaddr)
+				continue
+			}
+			fmt.Printf("        %v\n", ipaddr)
+		}
+		nss, err := currentStaticDNS(i)
+		if err != nil {
+			mainLog.Load().Warn().Err(err).Msg("failed to get DNS")
+		}
+		if len(nss) == 0 {
+			nss = currentDNS(i)
+		}
+		for i, dns := range nss {
+			if i == 0 {
+				fmt.Printf("DNS   : %s\n", dns)
+				continue
+			}
+			fmt.Printf("      : %s\n", dns)
+		}
+		println()
+		return nil
+	})
+	return nil
+}
+
+// InitInterfacesCmd creates the interfaces command with proper logic
+func InitInterfacesCmd() *cobra.Command {
+	listInterfacesCmd := &cobra.Command{
+		Use:   "list",
+		Short: "List network interfaces",
+		Args:  cobra.NoArgs,
+		PreRun: func(cmd *cobra.Command, args []string) {
+			checkHasElevatedPrivilege()
+		},
+		RunE: func(cmd *cobra.Command, args []string) error {
+			ic, err := NewInterfacesCommand()
+			if err != nil {
+				return err
+			}
+			return ic.ListInterfaces(cmd, args)
+		},
+	}
+
+	interfacesCmd := &cobra.Command{
+		Use:   "interfaces",
+		Short: "Manage network interfaces",
+		Args:  cobra.OnlyValidArgs,
+		ValidArgs: []string{
+			listInterfacesCmd.Use,
+		},
+	}
+	interfacesCmd.AddCommand(listInterfacesCmd)
+	rootCmd.AddCommand(interfacesCmd)
+
+	return interfacesCmd
+}