Hello, thanks for your suggestions. I'm afraid grep was designed as text-oriented tool. I'm not sure how it will handle CR and/or LF characters when matching pattern. IIRC grep has no multiline patterns, so it could basically fail. I guess it would suit 95% of my needs, I'm just trying to anticipate potential caveats. What about matching bytes values? Will grep accept syntax like \x55\x3a\xff\x10? Regards, Rob