finding empty files that are padded with zeros

Applications Filesystems, Disks and Memory
1

how can search for files that are non-zero length but are empty?

2

That's not really something that can happen. A non-zero file is, by definition, not empty.

To find a file that contains nothing but '0' characters. I'd try something like this

for file in <filenames>; do if egrep -v -e '^0*$' $file > /dev/null; then echo "do nothing" > /dev/null else echo "{}"; fi ; done