44 The script gets the nucleotide distribution of the input sequence list. It outputs two files. The first file shows the nucleotide distribution of the data. More precisely, a point (*x*, *y*) on the curve **A** shows that *y* sequences have *x* % of **A**.
46 The second plot shows the average nucleotide distribution for each position of the read. You can use it to detect a bias in the first nucleotides, for instance. A point *x*, *y* on the curve **A** shows that at the position *x*, there are *y*% of **A**. A point (*x*, *y*) on the curve **#** tells you that *y* % of the sequences contain not less than *x* nucleotides. By definition, this latter line is a decreasing function. It usually explains why the tail of the other curves are sometimes erratic: there are few sequences.