The man page description of the -I option implies that grep might output match information for a binary file if it hasn't "discovered" that the file is binary yet. It seems that even with -I Binary file matches may be reported, as this example on the attached file shows:
$ 'grep' -I -e '.' bca9b83eeb33810a61cca0485f504f98540156 Binary file bca9b83eeb33810a61cca0485f504f98540156 matches This seems like a bug, because it's clearly produced at a point when grep has already decided the file is binary, and scripts can reasonably expect that any matches that do occur in a so-far-unknown-to-be-binary file will conform to the output format specified by other other options (e.g. -n) and feature an actual file name. Britton
bca9b83eeb33810a61cca0485f504f98540156
Description: Binary data
