#!/bin/bash

if [ "$#" -ne 2 ]; then
    echo "Usage: $0 <file> <column_number>"
    exit 1
fi

file="$1"
col="$2"

awk -v c="$col" '
{
    if ($c ~ /^-?[0-9]+([.][0-9]+)?$/)
        sum += $c
}
END {
    print sum
}
' "$file"