grep output to show only matching file

You can use the Unix-style -l switch – typically terse and cryptic – or the equivalent --files-with-matches – longer and more readable.

The output of grep --help is not easy to read, but it's there:

-l, --files-with-matches  print only names of FILEs containing matches

Also remember one thing. Very important
You have to specify the command something like this to be more precise
grep -l "pattern" *

-l (that's a lower-case L).

grep -l 

(That's a lowercase L)