How to find the memory consumption of a particular process

How to measure actual memory usage of an application or process ?
How to find how much a specific process use ?
Just run pmem.sh script with a process name ! such as..

$ ./pmem.sh chrome
chrome's memory usage : 60.9 %

As you can see, you can find out what percentage does the process use of all memory.

$ cat pmem.sh
#!/bin/bash

if [ "$1" == "" ]; then
   echo "Please enter process name"
   exit 0
fi

p_count=`ps -eo comm | grep -wc "$1"`

if [ "$p_count" == "0" ]; then
   echo "Error: '$1' process don't exist"
   exit 0
fi


mem_usage=`ps -eo pmem,comm | grep -we "$1" | awk -F" " '{print  $1}' | paste -sd+ | bc`
echo "$1's memory usage : $mem_usage %"

exit 0