how to read main memory of linux code example

Example 1: linux command to check memory usage in percentage

$ free -t | awk 'NR == 2 {printf("Current Memory Utilization is : %.2f%"), $3/$2*100}'
or
$ free -t | awk 'FNR == 2 {printf("Current Memory Utilization is : %.2f%"), $3/$2*100}'

Current Memory Utilization is : 20.42%

Example 2: check vm ram details in linux

sudo dmidecode -t 17