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

Thank-you for the answers. bc was what I needed.

I dont know if posting the result is of any use. Anyway, this the final piece of code for exteracting the focal length of a photo and print it in decimal format. It is supposed to work for all cameras. Tested on 4 cameras of 3 different brands.

F="your_image.JPG"
EXIF=$(exiv2 -p v "$F")
FocalFractional=$( echo "$EXIF" | grep -E '[^ ]*  *Photo *FocalLength '| grep -iohE "[^ ]* *$" )
Formula="scale=2; "$FocalFractional
FocalDecimal=$( bc -l <<< "$Formula" )
echo $ FocalDecimal