var myCmd = &cobra.Command{ Use: "mycmd", Short: "A brief description of mycmd", Long: "A longer description of mycmd", Run: func(cmd *cobra.Command, args []string) { fmt.Println("Hello, world!") }, }In this example, we define a command called "myCmd" and set its Use to "mycmd". We also provide a brief and long description of the command. Finally, we define the Run function which will be executed when the command is run. In this case, it simply prints out "Hello, world!". This example demonstrates how easy it is to use the Command Use function with the cobra library to create command-line tools in Golang. The package library is github.com/spf13/cobra.