SSH Remote Shell

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

Download Chilkat Java Library

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[])
  {
    //  Important: It is helpful to send the contents of the
    //  ssh.LastErrorText property when requesting support.

    CkSsh ssh = new CkSsh();

    //  Any string automatically begins a fully-functional 30-day trial.
    boolean success;
    success = ssh.UnlockComponent("30-day trial");
    if (success != true) {
        System.out.println(ssh.lastErrorText());
        return;
    }

    //  Connect to an SSH server:
    String hostname;
    int port;

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

    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;
    termType = "dumb";
    int widthInChars;
    widthInChars = 120;
    int heightInChars;
    heightInChars = 40;
    //  Use 0 for pixWidth and pixHeight when the dimensions
    //  are set in number-of-chars.
    int pixWidth;
    pixWidth = 0;
    int pixHeight;
    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 "dir" command to retrieve the directory listing.
    success = ssh.ChannelSendString(channelNum,"dir" + "\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;
    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;
    cmdOutput = ssh.getReceivedText(channelNum,"ansi");
    if (cmdOutput == null ) {
        System.out.println(ssh.lastErrorText());
        return;
    }

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

    //  Disconnect
    ssh.Disconnect();
  }
}