map mapping mapq plot gnuplot

gistfile1.builder

$ cat plot_dist_mapq.rb 
#!/usr/bin/env ruby19
#
# time samtools view -F 4 ./0.bam | ./plot_dist_mapq.rb

h = Hash.new(0)
i = 0
STDIN.each do |l|
  $stderr.printf("\r%d", i) if i % 50000 == 0
  mq = l.split[4].to_i
  h[mq]= h[mq] + 1
  i = i + 1
end
$stderr.puts ""

File.open("data.txt", "w") do |df| 
  h.sort{|a,b| a[0]<=>b[0]}.each do |v|
    df.puts "#{v[0]}\t#{v[1]}"
  end
end

File.open("cfg.txt", "w") {|cfg| cfg.puts DATA.read }

`cat ./cfg.txt | gnuplot`
#`rm -f cfg.txt data.txt && ls -lach output.png`

__END__
#set terminal png nocrop size 750,450
#set key left top
set nokey
set xtics 2
set grid x y
#set datafile separator ","
set t png
#set xrange [0:800]
#set yrange [0:100]
set output "output.png"
set xlabel "# aligments"
set ylabel "Mapping quality"
set title "Mapping quality distribution"
plot "./data.txt" notitle with lines