#!/bin/bash
# print average temperature by year (special file with no header, columns = day month year daily_average_temperature

# get max years from file
maxyear=`tail < $1 | dm x3 | stats max`
#echo "maxyear = $maxyear"

# loop by year
for year in $(seq $maxyear)
do
    # select year and put in file
    dm "if x3=$year then INPUT else SKIP" < $1 > temp1
    # create single column file
    dm x4 < temp1 > temp2

    # generate stat output
    echo $year `stats mean < temp2`

    # end year loop
done