#!/bin/bash
# Script to check real memory usage
# L.Gill 02/05/06 - V.1.0
# ------------------------------------------
# ########  Script Modifications  ##########
# ------------------------------------------
# Who	 When	   What
# ---    ----      ----
# LGill	 17/05/06  "$percent" lt 1% fix - sed edits dc result beggining with "."
# 
#
#!/bin/bash
USAGE="`basename $0` [-w|--warning]<percent free> [-c|--critical]<percent free> [-n|--nocache]"
THRESHOLD_USAGE="WARNING threshold must be greater than CRITICAL: `basename $0` $*"
calc=/tmp/memcalc
percent_free=/tmp/mempercent
critical=""
warning=""
STATE_OK=0
STATE_WARNING=1
STATE_CRITICAL=2
STATE_UNKNOWN=3
nocache=0
# print usage
if [[ $# -lt 4 ]]
then
	echo ""
	echo "Wrong Syntax: `basename $0` $*"
	echo ""
	echo "Usage: $USAGE"
	echo ""
	exit 0
fi
# read input
while [[ $# -gt 0 ]]
  do
        case "$1" in
               -w|--warning)
               shift
               warning=$1
        ;;
               -c|--critical)
               shift
               critical=$1
        ;;
        
               -n|--nocache)
               nocache=1
        ;;
        esac
        shift
  done
# verify input
if [[ $warning -eq $critical || $warning -lt $critical ]]
then
	echo ""
	echo "$THRESHOLD_USAGE"
	echo ""
        echo "Usage: $USAGE"
	echo ""
        exit 0
fi

memoutput=`free -m | head -2 | tail -1`

# Total memory available
#total=`free -m | head -2 |tail -1 |gawk '{print $2}'`
total=`echo $memoutput | gawk '{print $2}'`
# Total memory used
#used=`free -m | head -2 |tail -1 |gawk '{print $3}'`
used=`echo $memoutput | gawk '{print $3}'`
# Calc total minus used
#free=`free -m | head -2 |tail -1 |gawk '{print $2-$3}'`
if [ "$nocache" -eq "1" ]; then
    free=`echo $memoutput | gawk '{print $2-$3+$7}'`
else
    free=`echo $memoutput | gawk '{print $2-$3}'`
fi

shared=`echo $memoutput | gawk '{print $5}'`
buffers=`echo $memoutput | gawk '{print $6}'`
cached=`echo $memoutput | gawk '{print $7}'`
# free=$free-$cached
# normal values
#echo "$total"MB total
#echo "$used"MB used
#echo "$free"MB free

# make it into % percent free = ((free mem / total mem) * 100)
echo "5" > $calc # decimal accuracy
echo "k" >> $calc # commit
echo "100" >> $calc # multiply
echo "$free" >> $calc # division integer
echo "$total" >> $calc # division integer
echo "/" >> $calc # division sign
echo "*" >> $calc # multiplication sign
echo "p" >> $calc # print
percent=`/usr/bin/dc $calc|/bin/sed 's/^\./0./'|/usr/bin/tr "." " "|/usr/bin/gawk {'print $1'}`
#percent1=`/usr/bin/dc $calc`
#echo "$percent1"
if [[ "$percent" -le  $warning ]]
        then
    string="WARNING"
    result=1
fi
if [[ "$percent" -le  $critical ]]
    then
    string="CRITICAL"
    result=2
fi
if [[ "$percent" -gt  $warning ]]
    then
    string="OK"
    result=0
fi

echo "$string - $free / $total MB ($percent%) Free Memory, Used: $used MB, Shared: $shared MB, Buffers: $buffers MB, Cached: $cached MB | total="$total"MB free="$free"MB used="$used"MB shared="$shared"$MB buffers="$buffers"MB cached="$cached"MB"
exit $result