awk histogram

hist.awk

BEGIN {
    range_min = 0.33
    range_max = 0.48
    range_size = range_max - range_min
    num_bins = int(range_size/0.003)
    bin_size = range_size / num_bins
    for(i=0;i<num_bins;++i) {
	freq[i] = 0
    }
}
{
    data = $2
    if(data>range_min&&data<range_max) {
	freq[int((data-range_min)/bin_size)]++
    }
}
END {
    for(i=0;i<num_bins;++i) {
	print range_min+bin_size*(0.5+i), freq[i]
    }
}