Java

SSH Remote Shell

See more SSH Examples

Demonstrates how to start a shell on a remote SSH server, run a command, and retrieve the output. Java

import com.chilkatsoft.*;

public class ChilkatExample {

  static {
    try {
        System.loadLibrary("chilkat");
    } catch (UnsatisfiedLinkError e) {
      System.err.println("Native code library failed to load.\n" + e);
      System.exit(1);
    }
  }

  public static void main(String argv[])
  {
    boolean success = false;

    // This example assumes the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    CkSsh ssh = new CkSsh();

    // Hostname may be an IP address or hostname:
    String hostname = "www.some-ssh-server.com";
    int port = 22;

    // Connect to an SSH server:
    success = ssh.Connect(hostname,port);
    if (success != true) {
        System.out.println(ssh.lastErrorText());
        return;
        }

    // Wait a max of 5 seconds when reading responses..
    ssh.put_IdleTimeoutMs(5000);

    // Authenticate using login/password:
    success = ssh.AuthenticatePw("myLogin","myPassword");
    if (success != true) {
        System.out.println(ssh.lastErrorText());
        return;
        }

    // Open a session channel.  (It is possible to have multiple
    // session channels open simultaneously.)
    int channelNum;
    channelNum = ssh.OpenSessionChannel();
    if (channelNum < 0) {
        System.out.println(ssh.lastErrorText());
        return;
        }

    // Some SSH servers require a pseudo-terminal
    // If so, include the call to SendReqPty.  If not, then 
    // comment out the call to SendReqPty.
    // Note: The 2nd argument of SendReqPty is the terminal type,
    // which should be something like "xterm", "vt100", "dumb", etc.
    // A "dumb" terminal is one that cannot process escape sequences.
    // Smart terminals, such as "xterm", "vt100", etc. process
    // escape sequences.  If you select a type of smart terminal,
    // your application will receive these escape sequences
    // included in the command's output.  Use "dumb" if you do not
    // want to receive escape sequences.  (Assuming your SSH
    // server recognizes "dumb" as a standard dumb terminal.)
    String termType = "dumb";
    int widthInChars = 120;
    int heightInChars = 40;
    // Use 0 for pixWidth and pixHeight when the dimensions
    // are set in number-of-chars.
    int pixWidth = 0;
    int pixHeight = 0;
    success = ssh.SendReqPty(channelNum,termType,widthInChars,heightInChars,pixWidth,pixHeight);
    if (success != true) {
        System.out.println(ssh.lastErrorText());
        return;
        }

    // Start a shell on the channel:
    success = ssh.SendReqShell(channelNum);
    if (success != true) {
        System.out.println(ssh.lastErrorText());
        return;
        }

    // Start a command in the remote shell.  This example
    // will send a "ls" command to retrieve the directory listing.
    success = ssh.ChannelSendString(channelNum,"ls\r\n","ansi");
    if (success != true) {
        System.out.println(ssh.lastErrorText());
        return;
        }

    // Send an EOF.  This tells the server that no more data will 
    // be sent on this channel.  The channel remains open, and
    // the SSH client may still receive output on this channel.
    success = ssh.ChannelSendEof(channelNum);
    if (success != true) {
        System.out.println(ssh.lastErrorText());
        return;
        }

    // Read whatever output may already be available on the
    // SSH connection.  ChannelReadAndPoll returns the number of bytes
    // that are available in the channel's internal buffer that
    // are ready to be "picked up" by calling GetReceivedText
    // or GetReceivedData.
    // A return value of -1 indicates failure.
    // A return value of -2 indicates a failure via timeout.

    // The ChannelReadAndPoll method waits
    // for data to arrive on the connection usingi the IdleTimeoutMs
    // property setting.  Once the first data arrives, it continues
    // reading but instead uses the pollTimeoutMs passed in the 2nd argument:
    // A return value of -2 indicates a timeout where no data is received.
    int n;
    int pollTimeoutMs = 2000;
    n = ssh.ChannelReadAndPoll(channelNum,pollTimeoutMs);
    if (n < 0) {
        System.out.println(ssh.lastErrorText());
        return;
        }

    // Close the channel:
    success = ssh.ChannelSendClose(channelNum);
    if (success != true) {
        System.out.println(ssh.lastErrorText());
        return;
        }

    // Perhaps we did not receive all of the commands output.
    // To make sure,  call ChannelReceiveToClose to accumulate any remaining
    // output until the server's corresponding "channel close" is received.
    success = ssh.ChannelReceiveToClose(channelNum);
    if (success != true) {
        System.out.println(ssh.lastErrorText());
        return;
        }

    // Let's pickup the accumulated output of the command:
    String cmdOutput = ssh.getReceivedText(channelNum,"ansi");
    if (ssh.get_LastMethodSuccess() != true) {
        System.out.println(ssh.lastErrorText());
        return;
        }

    // Display the remote shell's command output:
    System.out.println(cmdOutput);

    // Disconnect
    ssh.Disconnect();
  }
}