update completionExample

Signed-off-by: zhzhuang-zju <m17799853869@163.com>

pkg/karmadactl/completion/completion.go

@@ -54,16 +54,15 @@ var (
 	completionExample = templates.Examples(i18n.T(`
 		# Installing bash completion on Linux
 		## If bash-completion is not installed on Linux, install the 'bash-completion' package
+			1. apt-get install bash-completion
+			2. source /usr/share/bash-completion/bash_completion
 		## via your distribution's package manager.
 		## Load the %[1]s completion code for bash into the current shell
 		    source <(%[1]s completion bash)
-		## Write bash completion code to a file and source it from .bash_profile
-		    %[1]s completion bash > ~/.kube/completion.bash.inc
-		    printf "
-		      # %[1]s shell completion
-		      source '$HOME/.kube/completion.bash.inc'
-		      " >> $HOME/.bash_profile
-		    source $HOME/.bash_profile
+		## Or, write bash completion code to a file and source it from .bash_profile
+		    1. %[1]s completion bash > ~/.kube/completion.bash.inc
+		    2. echo "source '$HOME/.kube/completion.bash.inc'" >> $HOME/.bash_profile
+		    3. source $HOME/.bash_profile
 
 		# Load the %[1]s completion code for zsh[1] into the current shell
 		    source <(%[1]s completion zsh)

pkg/karmadactl/cordon/cordon.go

@@ -62,13 +62,17 @@ const (
 // NewCmdCordon defines the `cordon` command that mark cluster as unschedulable.
 func NewCmdCordon(f util.Factory, parentCommand string) *cobra.Command {
 	opts := CommandCordonOption{}
+
+	validArgs := []string{"cluster"}
+
 	cmd := &cobra.Command{
 		Use:                   "cordon CLUSTER",
 		Short:                 "Mark cluster as unschedulable",
 		Long:                  cordonLong,
 		Example:               fmt.Sprintf(cordonExample, parentCommand),
 		SilenceUsage:          true,
 		DisableFlagsInUseLine: true,
+		ValidArgsFunction:     utilcomp.SpecifiedResourceTypeAndNameCompletionFunc(f, validArgs),
 		RunE: func(_ *cobra.Command, args []string) error {
 			if err := opts.Complete(args); err != nil {
 				return err
@@ -96,6 +100,7 @@ func NewCmdUncordon(f util.Factory, parentCommand string) *cobra.Command {
 	opts := CommandCordonOption{}
 
 	validArgs := []string{"cluster"}
+
 	cmd := &cobra.Command{
 		Use:                   "uncordon CLUSTER",
 		Short:                 "Mark cluster as schedulable",