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 * license agreements. See the NOTICE file distributed with
 * this work for additional information regarding copyright
 * ownership. Elasticsearch licenses this file to you under
 * the Apache License, Version 2.0 (the "License"); you may
 * not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package org.elasticsearch.rest.action.cat;

import org.elasticsearch.client.Client;
import org.elasticsearch.common.inject.Inject;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.rest.*;

import java.io.IOException;
import java.util.Set;

import static org.elasticsearch.rest.RestRequest.Method.GET;

public class RestCatAction extends BaseRestHandler {

    private static final String CAT = "=^.^=";
    private static final String CAT_NL = CAT + "\n";
    private final String HELP;

    @Inject
    public RestCatAction(Settings settings, Client client, RestController controller, Set<AbstractCatAction> catActions) {
        super(settings, client);
        controller.registerHandler(GET, "/_cat", this);
        StringBuilder sb = new StringBuilder();
        sb.append(CAT).append(" try:\n");
        for (AbstractCatAction catAction : catActions) {
            catAction.documentation(sb);
        }
        HELP = sb.toString();
    }

    @Override
    public void handleRequest(final RestRequest request, final RestChannel channel) {
        try {
            boolean helpWanted = request.paramAsBoolean("h", false);
            if (helpWanted) {
                channel.sendResponse(new StringRestResponse(RestStatus.OK, HELP));
            } else {
                channel.sendResponse(new StringRestResponse(RestStatus.OK, CAT_NL));
            }
        } catch (Throwable t) {
            try {
                channel.sendResponse(new XContentThrowableRestResponse(request, t));
            } catch (IOException e1) {
                logger.error("Failed to send failure response", e1);
            }
        }
    }
}

@@ -1935,15 +1935,47 @@
 %22h%22,
+ request.paramAsBoolean(%22help%22,
  false)
+)
 ;%0A  

support help as well as h in direct cat call to list all actions