Find string in files

Taken from: http://www.liamdelahunty.com/tips/linux_find_string_files.phpfind . | xargs grep 'string' -slThe -s is for summary and won't display warning messages such as grep: ./directory-name: Is a directoryThe -l is for list, so we get just the filename and not all instances of the match displayed in the results.
Performing the search on the current directory I get:
./javascript_open_new_window_form.php
./excel_large_number_error.php
I find this useful for just quickly seeing which files contain a search time. I would normally limit the files searched with a command such as :
find . -iname '*php' | xargs grep 'string' -slAnother common search for me, is to just look at the recently updated files:
find . -iname '*php' -mtime -1 | xargs grep 'string' -slwould find only files edited today, whilst the following finds the files older than today:
find . -iname '*php' -mtime +1 | xargs grep 'string' -sl