Beware when piping awk | gnuplot or especially awk | awk: when printing numbers, awk by default prints them with something like %.6g, which can lose important amounts of precision. There are two ways this can happen. Firstly when numbers are implicitly converted to strings, eg for concatenation; and secondly when they are printed directly. These conversations are controlled by two different variables which may be set to printf directives to get higher precision.