When using the log function of awk, then what we get as a result is the natural logarithmic of the input, like:

`...$ awk 'BEGIN{print log(100)}'`

...$ 4.60517

So in order to obtain the logarithm of base 10 (or any other base), we just need to divide the result with the logarithm of the base, like:

`...$ awk 'BEGIN{print log(100)}/log(10)'`

...$ 2