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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one or more
3    * contributor license agreements.  See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * The ASF licenses this file to You under the Apache License, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License.  You may obtain a copy of the License at
8    *
9    *      http://www.apache.org/licenses/LICENSE-2.0
10   *
11   * Unless required by applicable law or agreed to in writing, software
12   * distributed under the License is distributed on an "AS IS" BASIS,
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   * See the License for the specific language governing permissions and
15   * limitations under the License.
16   */
17  
18  package examples.unix;
19  
20  import java.io.IOException;
21  import org.apache.commons.net.bsd.RCommandClient;
22  
23  import examples.util.IOUtil;
24  
25  /***
26   * This is an example program demonstrating how to use the RCommandClient
27   * class. This program connects to an rshell daemon and requests that the
28   * given command be executed on the server.  It then reads input from stdin
29   * (this will be line buffered on most systems, so don't expect character
30   * at a time interactivity), passing it to the remote process and writes
31   * the process stdout and stderr to local stdout.
32   * <p>
33   * On Unix systems you will not be able to use the rshell capability
34   * unless the process runs as root since only root can bind port addresses
35   * lower than 1024.
36   * <p>
37   * Example: java rshell myhost localusername remoteusername "ps -aux"
38   * <p>
39   * Usage: rshell <hostname> <localuser> <remoteuser> <command>
40   ***/
41  
42  // This class requires the IOUtil support class!
43  public final class rshell
44  {
45  
46      public static void main(String[] args)
47      {
48          String server, localuser, remoteuser, command;
49          RCommandClient client;
50  
51          if (args.length != 4)
52          {
53              System.err.println(
54                  "Usage: rshell <hostname> <localuser> <remoteuser> <command>");
55              System.exit(1);
56              return ; // so compiler can do proper flow control analysis
57          }
58  
59          client = new RCommandClient();
60  
61          server = args[0];
62          localuser = args[1];
63          remoteuser = args[2];
64          command = args[3];
65  
66          try
67          {
68              client.connect(server);
69          }
70          catch (IOException e)
71          {
72              System.err.println("Could not connect to server.");
73              e.printStackTrace();
74              System.exit(1);
75          }
76  
77          try
78          {
79              client.rcommand(localuser, remoteuser, command);
80          }
81          catch (IOException e)
82          {
83              try
84              {
85                  client.disconnect();
86              }
87              catch (IOException f)
88              {/* ignored */}
89              e.printStackTrace();
90              System.err.println("Could not execute command.");
91              System.exit(1);
92          }
93  
94  
95          IOUtil.readWrite(client.getInputStream(), client.getOutputStream(),
96                           System.in, System.out);
97  
98          try
99          {
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