see total memory usage linux code example
Example: 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%