Ejecutar comando y capturar su salida

[[seoane]]

Esta funcion nos permite ejecutar un comando como si nos encontraramos en una consola de DOS, y captura la salida en un string.

Código Delphi [-]
function IsWinNT: boolean;
var
  OSV: OSVERSIONINFO;
begin
  OSV.dwOSVersionInfoSize := sizeof(osv);
  GetVersionEx(OSV);
  result := OSV.dwPlatformId = VER_PLATFORM_WIN32_NT;
end;

function CmdExec(Cmd: string): string;
var
  Buffer: array[0..4096] of Char;
  si: STARTUPINFO;
  sa: SECURITY_ATTRIBUTES;
  sd: SECURITY_DESCRIPTOR;
  pi: PROCESS_INFORMATION;
  newstdin, newstdout, read_stdout, write_stdin: THandle;
  exitcod, bread, avail: Cardinal;
begin
  Result:= '';
  if IsWinNT then
  begin
    InitializeSecurityDescriptor(@sd, SECURITY_DESCRIPTOR_REVISION);
    SetSecurityDescriptorDacl(@sd, true, nil, false);
    sa.lpSecurityDescriptor := @sd;
  end
  else sa.lpSecurityDescriptor := nil;
  sa.nLength := sizeof(SECURITY_ATTRIBUTES);
  sa.bInheritHandle := TRUE;
  if CreatePipe(newstdin, write_stdin, @sa, 0) then
  begin
    if CreatePipe(read_stdout, newstdout, @sa, 0) then
    begin
      GetStartupInfo(si);
      with si do
      begin
        dwFlags := STARTF_USESTDHANDLES or STARTF_USESHOWWINDOW;
        wShowWindow := SW_HIDE;
        hStdOutput := newstdout;
        hStdError := newstdout;
        hStdInput := newstdin;
      end;
      Fillchar(Buffer, SizeOf(Buffer), 0);
      GetEnvironmentVariable('COMSPEC', @Buffer, SizeOf(Buffer) - 1);
      StrCat(@Buffer,PChar(' /c ' + Cmd));
      if CreateProcess(nil, @Buffer, nil, nil, TRUE, CREATE_NEW_CONSOLE, nil, nil, si, pi) then
      begin
        repeat
          PeekNamedPipe(read_stdout, @Buffer, SizeOf(Buffer) - 1, @bread, @avail, nil);
          if bread > 0 then
          begin
            Fillchar(Buffer, SizeOf(Buffer), 0);
            ReadFile(read_stdout, Buffer, bread, bread, nil);
            Result:= Result + String(PChar(@Buffer));
          end;
          Application.ProcessMessages;
          GetExitCodeProcess(pi.hProcess, exitcod);
        until (exitcod <> STILL_ACTIVE) and (bread = 0);
      end;
      CloseHandle(read_stdout);
      CloseHandle(newstdout);
    end;
    CloseHandle(newstdin);
    CloseHandle(write_stdin);
  end;
end;

Ejemplo de uso:

Código Delphi [-]
  ShowMessage(CmdExec('dir c:\'));
  ShowMessage(CmdExec('netstat -a -n'));