Linux bash - Loop though files and summary up a value in that files

Question

how would you do that

1. Loop through files based on a pattern
2. Extract a value from within that files (value is always there and a number)
3. Summarize all these values
4. echo the sum out

Many thanks in advance and greetings

Answer 1

To less info to be more exact. So I leave a template only:

let sum=0
for f in __PATTERN__
do
    value=__extract__from "$f"  # any functionality ...
    let sum+=value
done
printf "summary: %u\n" $sum