total-free-mem

#!/bin/bash
DEFAULT_WARNING=500
DEFAULT_CRITICAL=200
while getopts "h" opt; do
  case $opt in
    h)
      echo "Usage: $0 will alert if total memory is below warning $DEFAULT_WARNING or critical $DEFAULT_CRITICAL"
      echo "Optionally, you can symlink to $0_WARNING_CRITICAL where params are in mb (e.g. $0_"$DEFAULT_WARNING"_"$DEFAULT_CRITICAL")"
      exit 3
      ;;
    \?)
      echo "Invalid option: -$OPTARG" >&2
      ;;
  esac
done


PHYSICAL=`free -m | grep "buffers/cache:" | awk '{ print $4 }'`
SWAP=`free -m | grep "Swap:" | awk '{ print $2 }'`
TOTAL=`expr $PHYSICAL + $SWAP`
STATUS=3
MSG="UNKNOWN"

WARNING=`echo $0 | awk -F'_' '{print $2}'`
CRITICAL=`echo $0 | awk -F'_' '{print $3}'`
if [ "$WARNING" == "" ]; then
  WARNING=$DEFAULT_WARNING
fi
if [ "$CRITICAL" == "" ]; then
  CRITICAL=$DEFAULT_CRITICAL
fi

if [ "$TOTAL" -lt "$CRITICAL" ]; then
  STATUS=2
  MSG="CRITICAL - There is only $TOTAL MB of total memory left (swap + free buffers) [$WARNING/$CRITICAL alerts]"
elif [ "$TOTAL" -lt "$WARNING" ]; then
  STATUS=1
  MSG="WARNING - There is only $TOTAL MB of total memory left (swap + free buffers) [$WARNING/$CRITICAL alerts]"
else
  STATUS=0
  MSG="OK - Total memory free ($TOTAL) is adequate (swap + free buffers) [$WARNING/$CRITICAL alerts]"
fi
echo $STATUS total_free_mem total_free_mem=$TOTAL $MSG