Update description for sink flag

 - Add examples for broker, service and URI
 - Add note about default prefix and service alias

docs/cmd/kn_source_apiserver_create.md

@@ -30,7 +30,7 @@ kn source apiserver create NAME --resource RESOURCE --sink SINK
       --resource stringArray      Specification for which events to listen, in the format Kind:APIVersion:LabelSelector, e.g. "Event:v1:key=value".
                                   "LabelSelector" is a list of comma separated key value pairs. "LabelSelector" can be omitted, e.g. "Event:v1".
       --service-account string    Name of the service account to use to run this source
-  -s, --sink string               Addressable sink for events
+  -s, --sink string               Addressable sink for events. You can specify broker, service or URI. Examples: '--sink broker:nest' for 'nest' broker, '--sink https://event.receiver.uri' for an URI (identified by 'http' or 'https'), '--sink service:receiver' for 'receiver' knative service, you can also use prefix alias 'svc' for 'service'. If do not specify a prefix, it is considered as knative service, i.e. '--sink receiver' is same as '--sink svc:receiver'.
 ```
 
 ### Options inherited from parent commands

docs/cmd/kn_source_apiserver_update.md

@@ -30,7 +30,7 @@ kn source apiserver update NAME
       --resource stringArray      Specification for which events to listen, in the format Kind:APIVersion:LabelSelector, e.g. "Event:v1:key=value".
                                   "LabelSelector" is a list of comma separated key value pairs. "LabelSelector" can be omitted, e.g. "Event:v1".
       --service-account string    Name of the service account to use to run this source
-  -s, --sink string               Addressable sink for events
+  -s, --sink string               Addressable sink for events. You can specify broker, service or URI. Examples: '--sink broker:nest' for 'nest' broker, '--sink https://event.receiver.uri' for an URI (identified by 'http' or 'https'), '--sink service:receiver' for 'receiver' knative service, you can also use prefix alias 'svc' for 'service'. If do not specify a prefix, it is considered as knative service, i.e. '--sink receiver' is same as '--sink svc:receiver'.
 ```
 
 ### Options inherited from parent commands

docs/cmd/kn_source_binding_create.md

@@ -24,7 +24,7 @@ kn source binding create NAME --subject SUBJECT --sink SINK
       --ce-override stringArray   Cloud Event overrides to apply before sending event to sink. Example: '--ce-override key=value' You may be provide this flag multiple times. To unset, append "-" to the key (e.g. --ce-override key-).
   -h, --help                      help for create
   -n, --namespace string          Specify the namespace to operate in.
-  -s, --sink string               Addressable sink for events
+  -s, --sink string               Addressable sink for events. You can specify broker, service or URI. Examples: '--sink broker:nest' for 'nest' broker, '--sink https://event.receiver.uri' for an URI (identified by 'http' or 'https'), '--sink service:receiver' for 'receiver' knative service, you can also use prefix alias 'svc' for 'service'. If do not specify a prefix, it is considered as knative service, i.e. '--sink receiver' is same as '--sink svc:receiver'.
       --subject string            Subject which emits cloud events. This argument takes format kind:apiVersion:name for named resources or kind:apiVersion:labelKey1=value1,labelKey2=value2 for matching via a label selector
 ```
 

docs/cmd/kn_source_binding_update.md

@@ -24,7 +24,7 @@ kn source binding update NAME
       --ce-override stringArray   Cloud Event overrides to apply before sending event to sink. Example: '--ce-override key=value' You may be provide this flag multiple times. To unset, append "-" to the key (e.g. --ce-override key-).
   -h, --help                      help for update
   -n, --namespace string          Specify the namespace to operate in.
-  -s, --sink string               Addressable sink for events
+  -s, --sink string               Addressable sink for events. You can specify broker, service or URI. Examples: '--sink broker:nest' for 'nest' broker, '--sink https://event.receiver.uri' for an URI (identified by 'http' or 'https'), '--sink service:receiver' for 'receiver' knative service, you can also use prefix alias 'svc' for 'service'. If do not specify a prefix, it is considered as knative service, i.e. '--sink receiver' is same as '--sink svc:receiver'.
       --subject string            Subject which emits cloud events. This argument takes format kind:apiVersion:name for named resources or kind:apiVersion:labelKey1=value1,labelKey2=value2 for matching via a label selector
 ```
 

docs/cmd/kn_source_ping_create.md

@@ -26,7 +26,7 @@ kn source ping create NAME
   -h, --help                      help for create
   -n, --namespace string          Specify the namespace to operate in.
       --schedule string           Optional schedule specification in crontab format (e.g. '*/2 * * * *' for every two minutes. By default fire every minute.
-  -s, --sink string               Addressable sink for events
+  -s, --sink string               Addressable sink for events. You can specify broker, service or URI. Examples: '--sink broker:nest' for 'nest' broker, '--sink https://event.receiver.uri' for an URI (identified by 'http' or 'https'), '--sink service:receiver' for 'receiver' knative service, you can also use prefix alias 'svc' for 'service'. If do not specify a prefix, it is considered as knative service, i.e. '--sink receiver' is same as '--sink svc:receiver'.
 ```
 
 ### Options inherited from parent commands

docs/cmd/kn_source_ping_update.md

@@ -26,7 +26,7 @@ kn source ping update NAME
   -h, --help                      help for update
   -n, --namespace string          Specify the namespace to operate in.
       --schedule string           Optional schedule specification in crontab format (e.g. '*/2 * * * *' for every two minutes. By default fire every minute.
-  -s, --sink string               Addressable sink for events
+  -s, --sink string               Addressable sink for events. You can specify broker, service or URI. Examples: '--sink broker:nest' for 'nest' broker, '--sink https://event.receiver.uri' for an URI (identified by 'http' or 'https'), '--sink service:receiver' for 'receiver' knative service, you can also use prefix alias 'svc' for 'service'. If do not specify a prefix, it is considered as knative service, i.e. '--sink receiver' is same as '--sink svc:receiver'.
 ```
 
 ### Options inherited from parent commands

docs/cmd/kn_trigger_create.md

@@ -29,7 +29,7 @@ kn trigger create NAME --sink SINK
   -h, --help               help for create
       --inject-broker      Create new broker with name default through common annotation
   -n, --namespace string   Specify the namespace to operate in.
-  -s, --sink string        Addressable sink for events
+  -s, --sink string        Addressable sink for events. You can specify broker, service or URI. Examples: '--sink broker:nest' for 'nest' broker, '--sink https://event.receiver.uri' for an URI (identified by 'http' or 'https'), '--sink service:receiver' for 'receiver' knative service, you can also use prefix alias 'svc' for 'service'. If do not specify a prefix, it is considered as knative service, i.e. '--sink receiver' is same as '--sink svc:receiver'.
 ```
 
 ### Options inherited from parent commands

docs/cmd/kn_trigger_update.md

@@ -33,7 +33,7 @@ kn trigger update NAME
   -h, --help               help for update
       --inject-broker      Create new broker with name default through common annotation
   -n, --namespace string   Specify the namespace to operate in.
-  -s, --sink string        Addressable sink for events
+  -s, --sink string        Addressable sink for events. You can specify broker, service or URI. Examples: '--sink broker:nest' for 'nest' broker, '--sink https://event.receiver.uri' for an URI (identified by 'http' or 'https'), '--sink service:receiver' for 'receiver' knative service, you can also use prefix alias 'svc' for 'service'. If do not specify a prefix, it is considered as knative service, i.e. '--sink receiver' is same as '--sink svc:receiver'.
 ```
 
 ### Options inherited from parent commands

pkg/kn/commands/flags/sink.go

@@ -33,7 +33,18 @@ type SinkFlags struct {
 }
 
 func (i *SinkFlags) Add(cmd *cobra.Command) {
-	cmd.Flags().StringVarP(&i.sink, "sink", "s", "", "Addressable sink for events")
+	cmd.Flags().StringVarP(&i.sink,
+		"sink",
+		"s",
+		"",
+		"Addressable sink for events. "+
+			"You can specify broker, service or URI. "+
+			"Examples: '--sink broker:nest' for 'nest' broker, "+
+			"'--sink https://event.receiver.uri' for an URI (identified by 'http' or 'https'), "+
+			"'--sink service:receiver' for 'receiver' knative service, "+
+			"you can also use prefix alias 'svc' for 'service'. "+
+			"If do not specify a prefix, it is considered as knative service, "+
+			"i.e. '--sink receiver' is same as '--sink svc:receiver'.")
 
 	for _, p := range config.GlobalConfig.SinkMappings() {
 		//user configration might override the default configuration