How to find and replace all occurrences of a string recursively in a directory tree?

Question

Using just grep and sed, how do I replace all occurrences of:

a.example.com

with

b.example.com

within a

Answer 1

it is much simpler than that.

for i in `find *` ; do sed -i -- 's/search string/target string/g' $i; done

find i => will iterate over all the files in the folder and in subfolders.

sed -i => will replace in the files the relevant string if exists.