Get the Exit Status of a Remote SSH Command

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Demonstrates the Chilkat Ssh.GetChannelExitStatus method, which returns the remote process exit status for a channel. The only argument is the channel number. Call it only after ChannelReceivedExitStatus returns true.

import 'package:chilkat/chilkat.dart';

void main() {
  // Demonstrates the Ssh.GetChannelExitStatus method, which returns the remote process exit
  // status for a channel.  The only argument is the channel number.  Call it only after
  // ChannelReceivedExitStatus returns true.

  final ssh = CkSsh();

  final sshPort = 22;
  try {
    ssh.connect('ssh.example.com', sshPort);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // Normally you would not hard-code the password in source.  You should instead obtain it
  // from an interactive prompt, environment variable, or a secrets vault.
  final password = 'mySshPassword';

  try {
    ssh.authenticatePw('mySshLogin', password);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  final channelNum = ssh.openSessionChannel();
  if (channelNum < 0) {
    print(ssh.lastErrorText);
    return;
  }

  try {
    ssh.sendReqExec(channelNum, 'grep -q root /etc/passwd');
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // IMPORTANT: Set a read timeout.  ReadTimeoutMs defaults to 0, which means no limit -- without
  // it, this call waits forever if the server never sends channel close.
  ssh.readTimeoutMs = 15000;

  try {
    ssh.channelReceiveToClose(channelNum);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // Retrieve the exit status immediately, before calling unrelated SSH methods or releasing the
  // channel, because the completed channel record can be discarded.
  if (ssh.channelReceivedExitStatus(channelNum)) {
    final exitStatus = ssh.getChannelExitStatus(channelNum);
    print('Exit status: $exitStatus');

    // By convention, 0 means the remote command succeeded.
    if (exitStatus == 0) {
      print('The remote command succeeded.');
    } else {
      print('The remote command reported a failure.');
    }
  }

  ssh.disconnect();
}