checkRam.sh

#!/bin/sh

COUNT_SWAP=0 # Set this to 1 if you want to count free swapspace as free memory
WARN=$(( 2 * 1024 * 1024 )) # 2GB has to be in KB so multiply with 1024 2-times
INTERVAL=10 # check every 10 seconds
INTERVAL_N=30 # check every 30 seconds after the first notification

AVAILABLE_MEM=$((`awk '/MemAvailable/{print $2}' /proc/meminfo`)) # get available memory
AVAILABLE_SWAP=$((`awk '/SwapFree/{print $2}' /proc/meminfo`)) # get swap memory
INTV_C=$INTERVAL

while true; do
  AVAILABLE=$AVAILABLE_MEM
  if [ $COUNT_SWAP -gt 0 ]; then
	AVAILABLE=$(($AVAILABLE + $AVAILABLE_SWAP))
  fi

  if [ $AVAILABLE -lt $WARN ]; then
    # Send notification
     notify-send -u critical "Warning! Available RAM $(($AVAILABLE_MEM / 1024)) MB & $(($AVAILABLE_SWAP / 1024)) MB Swap"
    INTV_C=$INTERVAL_N
  else
    INTV_C=$INTERVAL
  fi
  sleep $INTV_C
done