Find a file.
find ./ -name "file_to_find.txt" 2>&1 | grep -v "Permission denied"Find In Files (File containing text), recursively from current folder.
grep -r "text_to_search_for" .Find in specific file types only.
grep -r 'testing' --include='*.php' --include='*.css'Count the number of lines in specific file by extension, including all sub directories.
find /file/directory/root -type f \( -name "*.php" -o -name "*.js" -o -name "*.css" \) -exec cat {} + | wc -l