MiPnamic

#!/bin/bash
echo "Average php-fpm process memory usage:"
PHPFPM="php-fpm" # it could be just php-fpm or php-fpm-X.X (eg. php-fpm-7.1) depending on configuration
AVG=$(ps --no-headers -o "rss,cmd" -C $PHPFPM | awk '{ sum+=$1 } END { printf ("%d%s\n", sum/NR/1024,"M") }')
QTY=$(ps -ylC $PHPFPM --sort:rss | tail -n +2 | wc -l)
echo "$AVG on $QTY processes"
exit 0