Linux – How to Automatically Run Firefox On Ubuntu Server System Startup

Those messages are nothing to worry about. The symlinks that are being complained about are only needed if you're using lilo as your bootloader, because it uses those symlinks to find your "current" kernel. Grub, being more flexible, has it's own way of doing things, and doesn't need the symlinks.

As of GNU coreutils 7.5 released in August 2009, sort allows a -h parameter, which allows numeric suffixes of the kind produced by du -h:

du -hs * | sort -h

If you are using a sort that does not support -h, you can install GNU Coreutils. E.g. on an older Mac OS X:

brew install coreutils
du -hs * | gsort -h

From sort manual:

-h, --human-numeric-sort compare human readable numbers (e.g., 2K 1G)