Display memory used by a program, using Linux cgroup

bromem.sh

#!/bin/sh

CGROUP_dir=/sys/fs/cgroup/memory
CGROUP_name=${0%.*}
CGROUP_limit=550502400

if [ "$EUID" != "0" ]
then
    sudo $0 $@
    exit $?
fi

displ() {
    MEM_USAGE=$(cat ${CGROUP_dir}/${CGROUP_name}/memory.usage_in_bytes)
    echo -e "\r~~~ $CPID ~~~ Current memory usage: ${MEM_USAGE}/${CGROUP_limit} ($((${MEM_USAGE} * 100 / ${CGROUP_limit}))%)"
}

mkdir -p ${CGROUP_dir}/${CGROUP_name}

echo $CGROUP_limit > ${CGROUP_dir}/${CGROUP_name}/memory.limit_in_bytes

trap quit TERM INT KILL

$@ &

CPID=$!
echo $CPID > ${CGROUP_dir}/${CGROUP_name}/tasks

zz=$$
(
    while kill -0 $CPID 2> /dev/null
    do
        sleep 1
        displ
    done
    kill $zz 2> /dev/null
) &
DPID=$!

quit() {
    kill -9 $CPID $DPID 2> /dev/null
}

while kill -0 $CPID 2> /dev/null && read -s 2> /dev/null
do
    displ
done

quit