Add command to connect an address

cmd/sing-box/cmd_tools.go

@@ -0,0 +1,35 @@
+package main
+
+import (
+	"context"
+
+	box "github.com/sagernet/sing-box"
+	E "github.com/sagernet/sing/common/exceptions"
+
+	"github.com/spf13/cobra"
+)
+
+var commandTools = &cobra.Command{
+	Use:   "tools",
+	Short: "experimental tools",
+}
+
+func init() {
+	mainCommand.AddCommand(commandTools)
+}
+
+func createPreStartedClient() (*box.Box, error) {
+	options, err := readConfigAndMerge()
+	if err != nil {
+		return nil, err
+	}
+	instance, err := box.New(context.Background(), options, nil)
+	if err != nil {
+		return nil, E.Cause(err, "create service")
+	}
+	err = instance.PreStart()
+	if err != nil {
+		return nil, E.Cause(err, "start service")
+	}
+	return instance, nil
+}