Monitor RAM usage during a siege

maxmem.sh

#!/bin/bash
#
# Russell Michell 2015 <russell.michell@deviate.net.nz>
#
# Custom wrapper around /proc/meminfo designed to be invoked by something like `watch -n1 maxmem.sh`
# and run on a server under siege for RAM usage analysis. The script outputs used memory in Mb to a file which can
# be further analysed thus:
#
# cat outfile.out | sort -nr | head -1
# 
# TODO:
# Modify the trap logic to detect an "upstream" quit from watch

OUTFILE="maxmem.out"

if [ ! -f $OUTFILE ]; then
        touch $OUTFILE
        chmod u+rw $OUTFILE
fi

MEM_TOTAL=$( sudo cat /proc/meminfo | awk '/MemTotal:/' | awk '{ print $2 }' )
MEM_FREE=$( sudo cat /proc/meminfo | awk '/MemFree:/' | awk '{ print $2 }' )
MEM_USED=$( echo "$MEM_TOTAL-$MEM_FREE" | bc )
MEM_CONV=$( echo "$MEM_USED/1024" | bc )
echo $MEM_CONV >> $OUTFILE

# Display peak usage when user quits the "parent" watch command
#trap "cat $OUTFILE | sort -nr ); exit(1)" INT TERM
#echo ${PIPESTATUS[0]} >> $OUTFILE