Try this for top 15 memory using processes (in % terms), all on one line...
ps aux | head -n 1 | cut -c 1-100; ps aux | sort -n -r -k 4 | grep -v COMMAND | head -n 15
ps aux | head -n 1 | cut -c 1-100; ps aux | sort -n -r -k 4 | grep -v COMMAND | head -n 15
