The Run part of the command gets executed only after the Execute is called on the command (you can also have a prerun-hook.)

So in your case when execute is called the runtime doesn't know about the flag. We should add the flags before the Execute is called on the command to make the runtime aware of it.

Code

package mainimport ("fmt""github.com/spf13/cobra")func main() {var strTmp stringmyCmd := &cobra.Command{Use: "myaction",Run: func(cmd *cobra.Command, args []string) {if len(args) == 1 {fmt.Println(strTmp)}},}myCmd.Flags().StringVarP((&strTmp), "test", "t", "", "Source directory to read from")myCmd.Execute()}

Output

⇒ go run main.go myaction --test "hello"hello

But there is an alternate solution to this, when you want to add the flags based on a condition. You can set DisableFlagParsing to true and parse it later.

Code

package mainimport ("fmt""github.com/spf13/cobra")func main() {myCmd := &cobra.Command{Use: "myaction",RunE: func(cmd *cobra.Command, args []string) error {if len(args) > 1 {flags := cmd.Flags()var strTmp string// Add the flagflags.StringVarP(&strTmp, "test", "t", "", "Source directory to read from")// Enable the flag parsingcmd.DisableFlagParsing = false// Parse the flagsif err := cmd.ParseFlags(args); err != nil {return err}fmt.Println(strTmp)}return nil},}// Disable flag parsingmyCmd.DisableFlagParsing = truemyCmd.Execute()}

Output

⇒ go run main.go myaction --test "hello"hello