Is there any file searching tool in Unix or Linux that does NOT display the text once it's been found? The grep family, by default, will display the line once it is found. I am looking for a method that will just search a file, and return whether the search was successful or not.. instead of displaying the result on screen.

From "man grep".

-q, --quiet, --silent -q, --quiet, --silent
Quiet; do not write anything to standard output. Exit immedi-
ately with zero status if any match is found, even if an error
was detected. Also see the -s or --no-messages option.