How do I search all files in a directory in Linux code example

Example 1: linux search all directories for file

find / -iname 'book1*'

Example 2: search all folders for file match linux

find . -name "foo*"

Example 3: how to search for a word in all files in a directory in linux

# this will search all subdirectories for text (no case sensitivity)
grep -inR "your text" .