Start a Remote Shell with QuickShell

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Demonstrates the Chilkat Ssh.QuickShell method, which starts a remote shell using the simplified sequence OpenSessionChannel → SendReqPty → SendReqShell. It takes no arguments and returns the shell channel number, or -1 on failure. The default PTY size is 80 columns by 24 rows.

import 'package:chilkat/chilkat.dart';

void main() {
  // Demonstrates the Ssh.QuickShell method, which starts a remote shell using the simplified
  // sequence OpenSessionChannel, SendReqPty, and SendReqShell.  It takes no arguments and returns
  // the shell channel number, or -1 on failure.  The default PTY size is 80 columns by 24 rows.

  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;
  }

  // Start the shell.  Note that QuickShell allocates a PTY, so the remote shell runs
  // interactively: it prints a command prompt and echoes the commands that are sent to it.
  final channelNum = ssh.quickShell();
  if (channelNum < 0) {
    print(ssh.lastErrorText);
    return;
  }

  // QuickShell returns as soon as the shell request is accepted -- it does not wait for or
  // consume the initial login text or prompt.
  try {
    ssh.channelSendString(channelNum, 'uname -a; echo DONE_MARKER\n', 'utf-8');
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // IMPORTANT: Set a read timeout before receiving until a match.  ReadTimeoutMs defaults to 0,
  // which means no limit -- without it, this call waits forever if the received data never
  // contains a match.
  ssh.readTimeoutMs = 15000;

  final caseSensitive = false;
  try {
    ssh.channelReceiveUntilMatch(channelNum, 'DONE_MARKER', 'utf-8', caseSensitive);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  final String output;
  try {
    output = ssh.getReceivedText(channelNum, 'utf-8');
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  print(output);

  ssh.disconnect();
}