Delphi ActiveX

SSH Exec (Execute Command Line)

Demonstrates running a single command on an SSH server with an exec request and retrieving its output. The example connects, authenticates, opens a session channel, sends the command, reads until the server closes the channel, and then checks the exit status.

Background: exec is the workhorse of SSH automation: it runs one command and the server closes the channel when the command exits, which is a definitive end-of-output signal. No PTY is involved, so the shell runs non-interactively — no prompt, no echoed input, no ANSI escape codes — giving clean, parseable output. Remember that an accepted exec request only means the request was accepted; the command's own success is reported through the channel exit status. Command syntax depends on the remote shell, which is the user's default shell on Linux/UNIX and usually CMD.EXE on Windows SSH servers.

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var
success: Integer;
ssh: TChilkatSsh;
hostname: WideString;
port: Integer;
password: WideString;
channelNum: Integer;
cmdOutput: WideString;

begin
success := 0;

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

//  Demonstrates running a single command on an SSH server with an exec request and retrieving
//  its output.  An exec request runs one command and the server closes the channel when it
//  finishes -- no PTY and no shell prompt are involved, so the output is clean and parseable.

ssh := TChilkatSsh.Create(Self);

//  The hostname may be a hostname or an IP address.
hostname := 'ssh.example.com';
port := 22;
success := ssh.Connect(hostname,port);
if (success = 0) then
  begin
    Memo1.Lines.Add(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 = 0) then
  begin
    Memo1.Lines.Add(ssh.LastErrorText);
    Exit;
  end;

//  Open a session channel.  Several session channels may be open at once on one connection.
channelNum := ssh.OpenSessionChannel();
if (channelNum < 0) then
  begin
    Memo1.Lines.Add(ssh.LastErrorText);
    Exit;
  end;

//  The command syntax depends on the remote system's shell.  On Linux/UNIX it is typically the
//  user's default shell; on Windows SSH servers it is usually CMD.EXE.
//    Linux/UNIX:  "ls -l /tmp"        or  "cd /etc; ls -la"
//    Windows:     "dir"               or  "\"cd \\temp&&dir\""
success := ssh.SendReqExec(channelNum,'ls -l /tmp');
if (success = 0) then
  begin
    Memo1.Lines.Add(ssh.LastErrorText);
    Exit;
  end;

//  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;

//  Read the output until the server sends channel close, which happens when the command exits.
success := ssh.ChannelReceiveToClose(channelNum);
if (success = 0) then
  begin
    Memo1.Lines.Add(ssh.LastErrorText);
    Exit;
  end;

cmdOutput := ssh.GetReceivedText(channelNum,'utf-8');
if (ssh.LastMethodSuccess = 0) then
  begin
    Memo1.Lines.Add(ssh.LastErrorText);
    Exit;
  end;
Memo1.Lines.Add(cmdOutput);

//  An accepted exec request does not mean the command succeeded.  Check the exit status.
if (ssh.ChannelReceivedExitStatus(channelNum)) then
  begin
    Memo1.Lines.Add('Exit status: ' + IntToStr(ssh.GetChannelExitStatus(channelNum)));
  end;

ssh.Disconnect();