Preparing to replace coreutils 8.13-3.3 (using .../coreutils_8.20-1_amd64.deb) ...
Unpacking replacement coreutils ...
dpkg: error processing /var/cache/apt/archives/coreutils_8.20-1_amd64.deb (--unpack):
trying to overwrite '/usr/share/man/man1/realpath.1.gz', which is also in package realpath 1.17
dpkg-deb: error: subprocess paste was killed by signal (Broken pipe)
Fixed with coreutils 8.20-3. Many happy DUs