docs: def which(software, strip_newline=True):
      '''get_install will return the path to where an executable is installed.
      '''
      if software is None:
          software = "singularity"
      cmd = ['which', software ]
      try:
          result = run_command(cmd)
          if strip_newline is True:
              result['message'] = result['message'].strip('\n')
          return result
  
      except: # FileNotFoundError
          return None