nagios监控内存

#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>"
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
# 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 
        ;; 
        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 
# Total memory available 
total=`free -m | head -2 |tail -1 |gawk '{print $2}'` 
# Total memory used 
used=`free -m | head -2 |tail -1 |gawk '{print $3}'` 
# Calc total minus used 
free=`free -m | head -2 |tail -1 |gawk '{print $4+$7}'` 
# normal values 
#echo "$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  $critical ]] 
        then 
                echo "CRITICAL - $free MB ($percent%) Free Memory" 
                exit 2 
fi 
if [[ "$percent" -le  $warning ]] 
        then 
                echo "WARNING - $free MB ($percent%) Free Memory" 
                exit 1 
fi 
if [[ "$percent" -gt  $warning ]] 
        then 
                echo "OK - $free MB ($percent%) Free Memory" 
                exit 0 
fi