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 text file under the /home/user/ directory tree recursively finding and replacing all occurrences in all files in sub-directories as well.

Answer 1

Try this: find /home/user/ -type f | xargs sed -i 's/a.example.com/b.example.com/g'

Answer 2

Exact duplicate of this question.