View Javadoc
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 org.apache.commons.net.examples.unix;
19  
20  import java.io.IOException;
21  
22  import org.apache.commons.net.bsd.RCommandClient;
23  import org.apache.commons.net.examples.util.IOUtil;
24  
25  /**
26   * This is an example program demonstrating how to use the RCommandClient class. This program connects to an rshell daemon and requests that the given command
27   * be executed on the server. It then reads input from stdin (this will be line buffered on most systems, so don't expect character at a time interactivity),
28   * passing it to the remote process and writes the process stdout and stderr to local stdout.
29   * <p>
30   * On UNIX systems you will not be able to use the rshell capability unless the process runs as root since only root can bind port addresses lower than 1024.
31   * <p>
32   * Example: java rshell myhost localusername remoteusername "ps -aux"
33   * <p>
34   * Usage: rshell <hostname> <localuser> <remoteuser> <command>
35   */
36  
37  // This class requires the IOUtil support class!
38  public final class rshell {
39  
40      public static void main(final String[] args) {
41  
42          if (args.length != 4) {
43              System.err.println("Usage: rshell <hostname> <localuser> <remoteuser> <command>");
44              System.exit(1);
45              return; // so compiler can do proper flow control analysis
46          }
47  
48          final RCommandClient client = new RCommandClient();
49          final String server = args[0];
50          final String localuser = args[1];
51          final String remoteuser = args[2];
52          final String command = args[3];
53  
54          try {
55              client.connect(server);
56          } catch (final IOException e) {
57              System.err.println("Could not connect to server.");
58              e.printStackTrace();
59              System.exit(1);
60          }
61  
62          try {
63              client.rcommand(localuser, remoteuser, command);
64          } catch (final IOException e) {
65              try {
66                  client.disconnect();
67              } catch (final IOException f) {
68                  /* ignored */
69              }
70              e.printStackTrace();
71              System.err.println("Could not execute command.");
72              System.exit(1);
73          }
74  
75          IOUtil.readWrite(client.getInputStream(), client.getOutputStream(), System.in, System.out);
76  
77          try {
78              client.disconnect();
79          } catch (final IOException e) {
80              e.printStackTrace();
81              System.exit(1);
82          }
83  
84          System.exit(0);
85      }
86  
87  }