Here are the several list of commands that can be used to search file.
grep "text string to search” directory-path
grep [option] "text string to search” directory-path
grep -r "text string to search” directory-path
grep -r -H "text string to search” directory-path
egrep -R "word-1|word-2” directory-path
egrep -w -R "word-1|word-2” directory-path