; return the 6-digit date string YYMMDD based on the present working
; directory.
; Assumes the pwd is of the currentt WD is YYYYMMDD

function datestr6_pwd

  pwd = file_basename(pwdf())
  case strlen(pwd) of
     6: return, pwd
     8: return, strmid(pwd,2,6)
  endcase
  
  
end