Cu is a function referring to gnu coreutils for easier and more efficient use.

cu

[ -z "$PS1" ] && return # bashcheck is only called via function
cu()
{
local program="$1"
local help="$*";
if [ -z "$program" ]; then echo "cu: Try \`cu --help' "; exit 1
elif [ "$program" == "--help" ]; then coreutils --help;
elif [ "$program" == "--version" ]; then coreutils --version;
else eval cmd=--coreutils-prog=$1; coreutils $cmd $help; fi
}