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
018package examples.unix;
019
020import java.io.IOException;
021import org.apache.commons.net.bsd.RCommandClient;
022
023import 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 ***/
041
042// This class requires the IOUtil support class!
043public final class rshell
044{
045
046    public static void main(String[] args)
047    {
048        String server, localuser, remoteuser, command;
049        RCommandClient client;
050
051        if (args.length != 4)
052        {
053            System.err.println(
054                "Usage: rshell <hostname> <localuser> <remoteuser> <command>");
055            System.exit(1);
056            return ; // so compiler can do proper flow control analysis
057        }
058
059        client = new RCommandClient();
060
061        server = args[0];
062        localuser = args[1];
063        remoteuser = args[2];
064        command = args[3];
065
066        try
067        {
068            client.connect(server);
069        }
070        catch (IOException e)
071        {
072            System.err.println("Could not connect to server.");
073            e.printStackTrace();
074            System.exit(1);
075        }
076
077        try
078        {
079            client.rcommand(localuser, remoteuser, command);
080        }
081        catch (IOException e)
082        {
083            try
084            {
085                client.disconnect();
086            }
087            catch (IOException f)
088            {/* ignored */}
089            e.printStackTrace();
090            System.err.println("Could not execute command.");
091            System.exit(1);
092        }
093
094
095        IOUtil.readWrite(client.getInputStream(), client.getOutputStream(),
096                         System.in, System.out);
097
098        try
099        {
100            client.disconnect();
101        }
102        catch (IOException e)
103        {
104            e.printStackTrace();
105            System.exit(1);
106        }
107
108        System.exit(0);
109    }
110
111}
112