アウトプットができる技術者に

it's a time to take a new step !

月末の計算

awk 
function eomth(yyyymm){
  yyyy=substr(yyyymm,1,4)
  mm=substr(yyyymm,5,2) + 1
  time = mktime(yyyy" "mm" 1 0 0 0") - 60 * 60 * 24 * 1
  return strftime("%Y%m%d", time)
}
{
   # test
   print eomth("201301") == "20130131" ? "." : "NG" # end of month 31th
   print eomth("201304") == "20130430" ? "." : "NG" # end of month 30th
   print eomth("201302") == "20130228" ? "." : "NG" # end of month 30th
   print eomth("201202") == "20120229" ? "." : "NG" # leap year
}'