Count number of Friday 13th's

#!/bin/bash

for year in {2000..2050}
do
  num=$(cal $year|awk '{print $6 " " $13 " " $20}'|tr ' ' '\n'|grep -c 13)
  echo "$year has $num Friday the 13th's"
done

#oneliner
#for year in `seq 2000 2050`;do echo "$year has $(cal $year|awk '{print $6 " " $13 " " $20}'|tr ' ' '\n'|grep -c 13) Friday the 13th's";done