AWK keep header of input file in output

Question

i have an input file that looks like this:

datetime,num1,num2
10-01-2015 00:00,1,2
10-01-2015 00:00,4,5

my awk code looks like this:

awk -F"," '{thisid=substr($1,1,10);if(lastid!=thisid)
{print lastid"|"cnt1"|"cnt2;cnt1=0;cnt2=0;lastid=thisid;}
if($2>=40){cnt1+=1;}if($3>=40){cnt2+=1;}
lastid=thisid;}' input > output

i want my output to have the header still:

datetime,num1,num2
10-01-2015,0,0
10-01-2015,0,0

currently output of header just look like this:

datetime|1|1

i dont want to manually print the header.

Answer 1

在左括号（{）之前，添加：

NR == 1 {print; next}