Useful commands for use with the Shell / Terminal. Spotlight tool - > ‘terminal’ to find on Mac OS.
PHP used in this case, replace ‘php’ with the file extension of your choice.
Find and replace a string across many files on MAC OS:
find . -name "*.php" -print | xargs sed -i "" 's/string to replace/replacement string/g'
Find and replace a string across many files on LINUX:
find . -name "*.php" -print | xargs sed -i 's/string to replace/replacement string/g'