SSH Remote Shell with Multiple Commands

See more SSH Examples

Demonstrates running several commands one after another in a single remote shell session, retrieving each command's output separately. No PTY is requested, so each command is followed by an echoed marker that signals where its output ends.

program ChilkatDemo;

// Demonstrates using the Chilkat Pascal wrapper via the C bridge DLL.
// Builds as a console application under Lazarus (FPC) or Delphi.

{$IFDEF FPC}
  {$MODE DELPHI}
{$ENDIF}
{$APPTYPE CONSOLE}

uses
  {$IFDEF UNIX}
  cthreads,
  {$ENDIF}
  SysUtils,
  CkDllLoader,
  Chilkat.Ssh;

// ---------------------------------------------------------------------------

procedure RunDemo;
var
  success: Boolean;
  ssh: TSsh;
  hostname: string;
  port: Integer;
  password: string;
  channelNum: Integer;
  caseSensitive: Boolean;
  cmdOutput: string;

begin
  success := False;

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

  //  Demonstrates running several commands one after another in a single remote shell session,
  //  retrieving each command's output separately.
  //  
  //  No PTY is requested, so the shell runs non-interactively and never prints a command prompt.
  //  Because there is no prompt to synchronize on, each command is followed by an "echo" of a
  //  unique marker, and the output is read up to that marker.

  ssh := TSsh.Create;

  hostname := 'ssh.example.com';
  port := 22;
  success := ssh.Connect(hostname,port);
  if (success = False) then
    begin
      WriteLn(ssh.LastErrorText);
      Exit;
    end;

  //  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.
  password := 'mySshPassword';

  success := ssh.AuthenticatePw('mySshLogin',password);
  if (success = False) then
    begin
      WriteLn(ssh.LastErrorText);
      Exit;
    end;

  channelNum := ssh.OpenSessionChannel();
  if (channelNum < 0) then
    begin
      WriteLn(ssh.LastErrorText);
      Exit;
    end;

  //  Start a shell WITHOUT requesting a PTY.  Without a PTY the shell sees it is connected to a
  //  raw data pipe and enters non-interactive mode: it suppresses the command prompt, does not
  //  echo typed commands back, and skips interactive login scripts.  The output is therefore
  //  clean and easily parseable -- but because no prompt is ever sent, code must not wait for
  //  one.  Instead, have each command print a predictable marker, or wait for EOF / channel close.
  success := ssh.SendReqShell(channelNum);
  if (success = False) then
    begin
      WriteLn(ssh.LastErrorText);
      Exit;
    end;

  //  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;

  caseSensitive := True;

  //  ---- 1st command: change directory ----
  success := ssh.ChannelSendString(channelNum,'cd /tmp; echo END_OF_CMD_1' + #10,'utf-8');
  if (success = False) then
    begin
      WriteLn(ssh.LastErrorText);
      Exit;
    end;

  success := ssh.ChannelReceiveUntilMatch(channelNum,'END_OF_CMD_1','utf-8',caseSensitive);
  if (success = False) then
    begin
      WriteLn(ssh.LastErrorText);
      Exit;
    end;

  //  Retrieving the text also clears the receive buffer, which matters: if the next marker were
  //  left in the buffer, the following receive would match immediately.
  cmdOutput := ssh.GetReceivedText(channelNum,'utf-8');
  if (ssh.LastMethodSuccess = False) then
    begin
      WriteLn(ssh.LastErrorText);
      Exit;
    end;
  WriteLn(cmdOutput);

  //  ---- 2nd command: directory listing ----
  success := ssh.ChannelSendString(channelNum,'ls; echo END_OF_CMD_2' + #10,'utf-8');
  if (success = False) then
    begin
      WriteLn(ssh.LastErrorText);
      Exit;
    end;

  success := ssh.ChannelReceiveUntilMatch(channelNum,'END_OF_CMD_2','utf-8',caseSensitive);
  if (success = False) then
    begin
      WriteLn(ssh.LastErrorText);
      Exit;
    end;

  cmdOutput := ssh.GetReceivedText(channelNum,'utf-8');
  if (ssh.LastMethodSuccess = False) then
    begin
      WriteLn(ssh.LastErrorText);
      Exit;
    end;
  WriteLn(cmdOutput);

  //  ---- 3rd command: long listing, then finish the session ----
  success := ssh.ChannelSendString(channelNum,'ls -l' + #10,'utf-8');
  if (success = False) then
    begin
      WriteLn(ssh.LastErrorText);
      Exit;
    end;

  //  No more input will be sent.
  success := ssh.ChannelSendEof(channelNum);
  if (success = False) then
    begin
      WriteLn(ssh.LastErrorText);
      Exit;
    end;

  success := ssh.ChannelReceiveToClose(channelNum);
  if (success = False) then
    begin
      WriteLn(ssh.LastErrorText);
      Exit;
    end;

  cmdOutput := ssh.GetReceivedText(channelNum,'utf-8');
  if (ssh.LastMethodSuccess = False) then
    begin
      WriteLn(ssh.LastErrorText);
      Exit;
    end;
  WriteLn(cmdOutput);

  ssh.Disconnect();


  ssh.Free;

end;

// ---------------------------------------------------------------------------

begin

  try
    RunDemo;
  except
    on E: Exception do
      WriteLn('Unhandled exception: ', E.ClassName, ': ', E.Message);
  end;

  WriteLn;
  {$IFDEF MSWINDOWS}
  WriteLn('Press Enter to exit...');
  ReadLn;
  {$ENDIF}
end.