#! /bin/bash
filename=$1
input=${filename:-/dev/stdin}

colNum=1

while read myLine
do

    sorted_line=$(cut -f $colNum $input | sort -g)

    echo $sorted_line

    read -a medianArr <<< $sorted_line

    middle=`expr ${#medianArr[@]} / 2`

    median=${medianArr[$middle]}


    echo $median

    colNum=`expr $colNum + 1`

done <${filename:-/dev/stdin}

% ./median test_file

% cat test_file | ./median

1
9
6
3
3
6