gistfile1.sh

#!/bin/bash
# Print average apache process size
# Licensed under GPL v3 or later
#
# =| USAGE |===================================================================
#
#  echo <apache-parent-process-id> | ./apache_avg_procsize.sh
#
# On Debian this translates to:
#
#  cat /var/run/apache2.pid | ./apache_avg_procsize.sh
#
# On Redhat:
#
#  cat /var/run/httpd.pid | ./apache_avg_procsize.sh
#

if [ ! "$UID" -eq "0" ]
then echo "WARNING: This should be run as root." >&2; fi

read APACHE_PID
MEM_TOTAL=$(cat /proc/meminfo | awk '/MemTotal/ {print $2}')

# Before someone WTFs the next ps line..
# h: omit header
# opid: only print 'pid' column.
# ppid: print only processes whose parent process' id equal to given pid.
HTTPD_AVG_MEM=$(ps --ppid $APACHE_PID h opid |
# Use pmap to retrieve process memory consumption
while read pid; do
  pmap -d $pid |
  tail -n1 |
  sed 's/.*private: \([0-9]*\).*/\1/';
done |
# Get average
awk '{ SUM += $1 } END {print SUM/NR}')

echo "scale=2; $HTTPD_AVG_MEM / 1024" | bc