rtorrent@codex:~$ ps -A --sort -rss -o comm,pmem | head -n 11
COMMAND         %MEM
deluged          0.6
python           0.6
Plex Media Serv  0.3
deluge-web       0.3
apache2          0.1
apache2          0.1
apache2          0.1
apache2          0.1
Plex DLNA Serve  0.1
apache2          0.1
rtorrent@codex:~$ free
             total       used       free     shared    buffers     cached
Mem:       8169692    8050696     118996          0     168212    7231712
-/+ buffers/cache:     650772    7518920
Swap:      8380412         52    8380360
rtorrent@codex:~$