How to check if a file contains only zeros in a Linux shell?

Question

How to check if a large file contains only zero bytes (\'\\0\') in Linux using a shell command? I can write a small program for this but this seems to be an ov

Answer 1

The "file" /dev/zero returns a sequence of zero bytes on read, so a cmp file /dev/zero should give essentially what you want (reporting the first different byte just beyond the length of file).