log10 reads its standard input, which should be in text form and should contain two positive numbers (x and y) on each line, separated by spaces or tabs. The standard output of log10 contains four columns of numbers, separated by spaces: the common (base 10) logarithms of x and y, and the x and y values. To avoid underflow, if any input is less than MINDOUBLE (defined in <values.h> as the smallest positive value that can be represented as a double-precision floating point quantity), it is replaced by that value.
This program is part of the psd package, distributed with the DB Software Package, version 9.3 and later.