If you run `grep -h . file1 file2 file3 ...`, the output is not prefixed with the filename. If you run `grep -h . file1` however, the filename will incorrectly prefix the output.
If you run `grep -h . file1 file2 file3 ...`, the output is not prefixed with the filename. If you run `grep -h . file1` however, the filename will incorrectly prefix the output.