Linux: Find all occurrences of “string1” in files under a directory and replace them with “string2”

Question

In linux, what's a good way to find all occurrences of "string1" in files under a directory and replace them with "string2"?

Answer 1

Fairly basic. Use sed with file globbing. Unless you mean every file in directory and subdirectories?

sed -i 's/string1/string2/g' /path_to_dir/*

Edit: In the case of literally everything under the directory

find /path_to_dir/ -type f -exec sed -i 's/string1/string2/g' '{}' +