You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: shell.go
    path of file: ./repos/seaweedfs/weed/command
    
    the code of the file until where you have to start completion: package command

import (
	"fmt"
	"github.com/seaweedfs/seaweedfs/weed/pb"

	"github.com/seaweedfs/seaweedfs/weed/security"
	"github.com/seaweedfs/seaweedfs/weed/shell"
	"github.com/seaweedfs/seaweedfs/weed/util"
)

var (
	shellOptions      shell.ShellOptions
	shellInitialFiler *string
	shellCluster      *string
)

func init() {
	cmdShell.Run = runShell // break init cycle
	shellOptions.Masters = cmdShell.Flag.String("master", "", "comma-separated master servers, e.g. localhost:9333")
	shellOptions.FilerGroup = cmdShell.Flag.String("filerGroup", "", "filerGroup for the filers")
	shellInitialFiler = cmdShell.Flag.String("filer", "", "filer host and port, e.g. localhost:8888")
	shellCluster = cmdShell.Flag.String("cluster", "", "cluster defined in shell.toml")
}

var cmdShell = &Co
    
func runShell(command *Command, args []string) bool {

	util.LoadConfiguration("security", false)
	shellOptions.GrpcDialOption = security.LoadClientTLS(util.GetViper(), "grpc.client")

	if *shellOptions.Masters == "" {
		util.LoadConfiguration("shell", false)
		v := util.GetViper()
		cluster := v.GetString("cluster.default")
		if *shellCluster != "" {
			cluster = *shellCluster
		}
		if cluster == "" {
			*shellOptions.Masters = "localhost:9333"
		} else {
			*shellOptions.Masters = v.GetString("cluster." + cluster + ".master")
			*shellInitialFiler = v.GetString("cluster." + cluster + ".filer")
			fmt.Printf("master: %s filer: %s\n", *shellOptions.Masters, *shellInitialFiler)
		}
	}

	shellOptions.FilerAddress = pb.ServerAddress(*shellInitialFiler)
	shellOptions.Directory = "/"

	shell.RunShell(shellOptions)

	return true

}