add global persistent flag for config file with default value

cmd/root.go

@@ -6,14 +6,18 @@ import (
 	"github.com/spf13/cobra"
 )
 
-// rootCmd represents the base command when called without any subcommands
-var rootCmd = &cobra.Command{
+var (
+	cfgFile string
+
+	// rootCmd represents the base command when called without any subcommands
+	rootCmd = &cobra.Command{
 		Use:   "ProxySwitcher",
 		Short: "A simple internet proxy switching tool",
 		// Uncomment the following line if your bare application
 		// has an action associated with it:
 		// Run: func(cmd *cobra.Command, args []string) { },
-}
+	}
+)
 
 // Execute adds all child commands to the root command and sets flags appropriately.
 // This is called by main.main(). It only needs to happen once to the rootCmd.
@@ -25,14 +29,22 @@ func Execute() {
 }
 
 func init() {
+	cobra.OnInitialize(initConfig)
+
 	// Here you will define your flags and configuration settings.
 	// Cobra supports persistent flags, which, if defined here,
 	// will be global for your application.
 
-	// rootCmd.PersistentFlags().StringVar(&cfgFile, "config", "", "config file (default is $HOME/.ProxySwitcher.yaml)")
+	rootCmd.PersistentFlags().StringVar(&cfgFile, "configs", "c", "configs file (default is 'configs.json' in cwd)")
 
 	// Cobra also supports local flags, which will only run
 	// when this action is called directly.
 
 	// rootCmd.Flags().BoolP("toggle", "t", false, "Help message for toggle")
 }
+
+func initConfig() {
+	if cfgFile == "" {
+		cfgFile = "configs.json"
+	}
+}