Dart

Set a TTY Mode for an SSH PTY Request

Demonstrates the Chilkat Ssh.SetTtyMode method, which adds or updates one TTY mode to be included in a later SendReqPty request. The first argument is the mode name and the second is its integer value. Call it once per mode, before requesting the PTY.

Background: TTY modes are the terminal settings a PTY is created with — the same knobs stty exposes. The classic use is SetTtyMode("ECHO", 0), which stops the terminal from echoing input; that is how a password prompt keeps typed characters off the screen. Modes accumulate on the object and are sent with the next PTY request.

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Dart

import 'package:chilkat/chilkat.dart';

void main() {
  // Demonstrates the Ssh.SetTtyMode method, which adds or updates one TTY mode to be included in
  // a later SendReqPty request.  The 1st argument is the mode name and the 2nd is its integer
  // value.  Call it once per mode, before SendReqPty.

  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;
  }

  // Open a session channel.  A negative return value indicates failure.
  final channelNum = ssh.openSessionChannel();
  if (channelNum < 0) {
    print(ssh.lastErrorText);
    return;
  }

  // Request that the allocated terminal not echo input.
  try {
    ssh.setTtyMode('ECHO', 0);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // The modes set above are included in the PTY request.
  try {
    ssh.sendReqPty(channelNum, 'xterm', 80, 24, 0, 0);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

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

  ssh.disconnect();
}