001    /*
002     * Licensed to the Apache Software Foundation (ASF) under one or more
003     * contributor license agreements.  See the NOTICE file distributed with
004     * this work for additional information regarding copyright ownership.
005     * The ASF licenses this file to You under the Apache License, Version 2.0
006     * (the "License"); you may not use this file except in compliance with
007     * the License.  You may obtain a copy of the License at
008     *
009     *      http://www.apache.org/licenses/LICENSE-2.0
010     *
011     * Unless required by applicable law or agreed to in writing, software
012     * distributed under the License is distributed on an "AS IS" BASIS,
013     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014     * See the License for the specific language governing permissions and
015     * limitations under the License.
016     */
017    
018    package examples.unix;
019    
020    import java.io.IOException;
021    import org.apache.commons.net.bsd.RCommandClient;
022    
023    import examples.util.IOUtil;
024    
025    /***
026     * This is an example program demonstrating how to use the RCommandClient
027     * class. This program connects to an rshell daemon and requests that the
028     * given command be executed on the server.  It then reads input from stdin
029     * (this will be line buffered on most systems, so don't expect character
030     * at a time interactivity), passing it to the remote process and writes
031     * the process stdout and stderr to local stdout.
032     * <p>
033     * On Unix systems you will not be able to use the rshell capability
034     * unless the process runs as root since only root can bind port addresses
035     * lower than 1024.
036     * <p>
037     * Example: java rshell myhost localusername remoteusername "ps -aux"
038     * <p>
039     * Usage: rshell <hostname> <localuser> <remoteuser> <command>
040     * <p>
041     ***/
042    
043    // This class requires the IOUtil support class!
044    public final class rshell
045    {
046    
047        public static final void main(String[] args)
048        {
049            String server, localuser, remoteuser, command;
050            RCommandClient client;
051    
052            if (args.length != 4)
053            {
054                System.err.println(
055                    "Usage: rshell <hostname> <localuser> <remoteuser> <command>");
056                System.exit(1);
057                return ; // so compiler can do proper flow control analysis
058            }
059    
060            client = new RCommandClient();
061    
062            server = args[0];
063            localuser = args[1];
064            remoteuser = args[2];
065            command = args[3];
066    
067            try
068            {
069                client.connect(server);
070            }
071            catch (IOException e)
072            {
073                System.err.println("Could not connect to server.");
074                e.printStackTrace();
075                System.exit(1);
076            }
077    
078            try
079            {
080                client.rcommand(localuser, remoteuser, command);
081            }
082            catch (IOException e)
083            {
084                try
085                {
086                    client.disconnect();
087                }
088                catch (IOException f)
089                {}
090                e.printStackTrace();
091                System.err.println("Could not execute command.");
092                System.exit(1);
093            }
094    
095    
096            IOUtil.readWrite(client.getInputStream(), client.getOutputStream(),
097                             System.in, System.out);
098    
099            try
100            {
101                client.disconnect();
102            }
103            catch (IOException e)
104            {
105                e.printStackTrace();
106                System.exit(1);
107            }
108    
109            System.exit(0);
110        }
111    
112    }
113