my script name is 1. when i type in 1 2012 12 12. it shows current date calendar and when i enter a invaild date like 1 2323232 cal gives me a error so how could i put that in if loop that if it gives error it echos date is not validyear=$(echo $year | bc)month=$(echo $month | bc)day=$(echo $day | bc)cal $day $month $yearif [ $? -eq 0];        then        echo Date is validelse        echo Date in not validfi
how to write this if command?
bash;cal