Change string in many files at once and MUCH more.

Change string in many files at once and more.

Find all files that contain string XXX in them, change the string from XXX to YYY, make a backup copy of the file and save a list of files changed in /tmp/fileschanged.

find . -type f -exec grep -l XXX {} \;|tee /tmp/fileschanged|xargs perl -pi.bak -e 's/XXX/YYY/g'