'du -s' - includes directories
the 'find' solution above is recursive

largest FILE in the CURRENT directory
find . ! -name . -prune -type f -ls | sort -r -k 7,7 | head -1

Assuming the file name does contain embedded space [in ksh]:
A=$(find . ! -name . -prune -type f -ls | sort -r -k 7,7 | nawk 'FNR==1{print $NF; exit}')