How to calculate the log of a number using bc?

Question

I want to calculate the log (base 10) of a number. How can I do this using bc?

Answer 1

Invoke bc with the -l option (to enable the math library) like so:

$ echo 'l(100)/l(10)' | bc -l
2.00000000000000000000

Use the l function which is the natural log. Take the natural log of the number you are interested in then divide it by the natural log of 10.