floating-point operations with bash

Question

how can I transform the string \"620/100\" into \"6.2\" in a bash script

The context of my question is about image processing. EXIF data are coding the focal length in f

Answer 1

Use bc -l

bc -l <<< "scale=2; 620/100"
6.20

OR awk:

awk 'BEGIN{printf "%.2f\n", (620/100)}'
6.20