How to use grep to detect if specific text is found inside a folder?

Question

I want to get an exit code only if a specific text is found in a set of log file.

If no matches are found, or no files are present the command should pass successfully.

Grep should be silent, as I don't want to see the matches. I only want to know if the pattern was found (using exit code).

Somehow it seems that if use quiet mode to silence grep, the result code will always be success.

Answer 1

Works for me

mkdir _ ; cd _ ; touch a ; echo b > b
grep -q c * || echo $?
1

0 means success, 1 means no matches. In a condition, you don't need the $?, you can use the command directly:

if grep -q c * ; then
    echo Found
else
    echo Not found
fi

Answer 2

Solution was to just use ! grep ... >/dev/null.