Replace string in all files using sed in linux

Replaces all “OLDSTRING” to “NEWSTRING” in all files $ grep -rl OLDSTRING * | sort | uniq | xargs sed -i -e ‘s/OLDSTRING/NEWSTRING/’ or using find: find */public_html/ -iname ‘*.php’ -exec sed -i -e ‘s/OLDSTRING/NEWSTRING/’ {} \;