See memory being used by a docker container

docker-mem.sh

#!/bin/bash

getmem() {
  name=$1

  image=$(docker ps | grep $name | awk '{print $2}')
  short=$(docker ps | grep $name | awk '{print $1}')
  long=$(docker inspect $short | grep ID | awk '{print $2}' | sed 's~[",]~~g')

  rss=$(grep total_rss /sys/fs/cgroup/memory/lxc/$long/memory.stat | awk '{print $2}')

  mem=$(echo "($rss/1024)/1024" | bc)

  echo "$image is using $mem MB"
}

name=$1

if [ -z $name ];
then
  echo "get all containers"
  for id in $(docker ps  | grep -v '^CONTAINER ID' | awk '{print $1}')
  do
    getmem $id
  done
else
  getmem $name
fi