code: def run(cmd_str,cwd='.',verbose=False):
      
      bwd = os.getcwd()
      os.chdir(cwd)
      try:
          exe_name = cmd_str.split()[0]
          if "window" in platform.platform().lower():
              if not exe_name.lower().endswith("exe"):
                  raw = cmd_str.split()
                  raw[0] = exe_name + ".exe"
                  cmd_str = ' '.join(raw)
          else:
              if exe_name.lower().endswith('exe'):
                  raw = cmd_str.split()
                  exe_name = exe_name.replace('.exe','')
                  raw[0] = exe_name
                  cmd_str = '{0} {1} '.format(*raw)
              if os.path.exists(exe_name) and not exe_name.startswith('./'):
                  cmd_str = "./" + cmd_str
  
  
      except Exception as e:
          os.chdir(bwd)
          raise Exception("run() error preprocessing command line :{0}".format(str(e)))
      if verbose:
          print("run():{0}".format(cmd_str))
  
      try:
          ret_val = os.system(cmd_str)
      except Exception as e:
          os.chdir(bwd)
          raise Exception("run() raised :{0}".format(str(e)))
      os.chdir(bwd)
      if "window" in platform.platform().lower():
          if ret_val != 0:
              raise Exception("run() returned non-zero")
docs: an OS agnostic function to execute a command line
  
      Parameters
      ----------
      cmd_str : str
          the str to execute with os.system()
  
      cwd : str
          the directory to execute the command in
  
      verbose : bool
          flag to echo to stdout complete cmd str
  
      Note
      ----
      uses platform to detect OS and adds .exe suffix or ./ prefix as appropriate
  
      for Windows, if os.system returns non-zero, raises exception
  
      Example
      -------
      ``>>>import pyemu``
  
      ``>>>pyemu.helpers.run("pestpp pest.pst")``