update resource builder error message to be more clear

pkg/kubectl/resource/builder.go

@@ -333,7 +333,7 @@ func (b *Builder) ResourceTypeOrNameArgs(allowEmptySelector bool, args ...string
 		}
 	case len(args) == 0:
 	default:
-		b.errs = append(b.errs, fmt.Errorf("when passing arguments, must be resource or resource and name"))
+		b.errs = append(b.errs, fmt.Errorf("arguments must consist of a resource or a resource and name"))
 	}
 	return b
 }
@@ -362,7 +362,12 @@ func hasCombinedTypeArgs(args []string) (bool, error) {
 	case hasSlash > 0 && hasSlash == len(args):
 		return true, nil
 	case hasSlash > 0 && hasSlash != len(args):
-		return true, fmt.Errorf("when passing arguments in resource/name form, all arguments must include the resource")
+		baseCmd := "cmd"
+		if len(os.Args) > 0 {
+			baseCmdSlice := strings.Split(os.Args[0], "/")
+			baseCmd = baseCmdSlice[len(baseCmdSlice)-1]
+		}
+		return true, fmt.Errorf("there is no need to specify a resource type as a separate argument when passing arguments in resource/name form (e.g. '%s get resource/<resource_name>' instead of '%s get resource resource/<resource_name>'", baseCmd, baseCmd)
 	default:
 		return false, nil
 	}

pkg/kubectl/resource/builder_test.go

@@ -1231,7 +1231,7 @@ func TestHasNames(t *testing.T) {
 		{
 			args:            []string{"rc/foo", "bar"},
 			expectedHasName: false,
-			expectedError:   fmt.Errorf("when passing arguments in resource/name form, all arguments must include the resource"),
+			expectedError:   fmt.Errorf("there is no need to specify a resource type as a separate argument when passing arguments in resource/name form (e.g. 'resource.test get resource/<resource_name>' instead of 'resource.test get resource resource/<resource_name>'"),
 		},
 	}
 	for _, test := range tests {