A co-worker asked me if it is possible to grep arbitrary binary strings, e.g. sequences of non-printable ASCII characters. It turns out that GNU grep does understand binary strings if we use Perl-regex via the -P option.
[sh@pc ~]$ grep -slrP '\x05\x00\xc0' /boot /boot/grub/ffs_stage1_5 /boot/grub/ufs2_stage1_5 /boot/grub/stage2 /boot/efi/EFI/redhat/grub.efi /boot/vmlinuz-18.104.22.168-213.fc11.x86_64
I couldn’t find this when Googling for “grep binary” so I thought I should pen it down here.