files in Linux that begin with a period are hidden.
ls lists files.
-a includes hidden files.
-l shows permissions and ownership.
-R is the recursive flag.
So this command would show every single file in /images and it’s sub-directories:
ls -laR /images
You could pipe that with grep, which is a powerful searching tool and just search for .mntcheck
ls -laR /images | grep .mntcheck
That will only show all instances of .mntcheck inside the /images directory.
There should be two.