docs: def _read_starlog(self):
          """ read history.data or star.log file again"""
  
          sldir   = self.sldir
          slname  = self.slname
          slaname = slname+'sa'
  
          if not os.path.exists(sldir+'/'+slaname):
              print('No '+self.slname+'sa file found, create new one from '+self.slname)
              _cleanstarlog(sldir+'/'+slname)
          else:
              if self.clean_starlog:
                  print('Requested new '+self.slname+'sa; create new from '+self.slname)
                  _cleanstarlog(sldir+'/'+slname)
              else:
                  print('Using old '+self.slname+'sa file ...')
  
          cmd=os.popen('wc '+sldir+'/'+slaname)
          cmd_out=cmd.readline()
          cnum_cycles=cmd_out.split()[0]
          num_cycles=int(cnum_cycles) - 6
  
          filename=sldir+'/'+slaname
  
          header_attr,cols,data = _read_mesafile(filename,data_rows=num_cycles)
  
          self.cols        = cols
          self.header_attr = header_attr
          self.data        = data