#!/bin/bash
# Usage: "Linux - RAM usage monitor.sh 80 95"
# 
# Description:
#   This script is used from inside of Tactical RMM instances to check the RAM usage. 
#   This script should be deployed as a check script.
#
# Options:
#   Arg1 - Warning limit
#   Arg2 - Error limit
#
# Author: D. de Kooker (info@dcomputers.nl)
# Sources: https://www.activexperts.com/support/network-monitor/online/linux/
# Changelog :
#   27-06-2022 - Initial script from source, tweaked for my environment

#region Parameters, functions and global variables
  nWarnMemoryUsage=$1
  nMaxMemoryUsage=$2
#endregion
# Validate number of arguments
if [ $# -ne 2 ] ; then
  echo "UNCERTAIN: Invalid number of arguments - Usage: memory nMaxMemoryUsage"
  exit 1
fi

# Validate numeric parameter nMaxMemoryUsage
regExpNumber='^[0-9]+$'
if ! [[ $1 =~ $regExpNumber ]] ; then
  echo "UNCERTAIN: Invalid argument: nMaxMemoryUsage (number expected)"
  exit 1
fi

# Check the memory usage
nMemoryPercentage=`ps -A -o pmem | tail -n+2 | paste -sd+ | bc`
nMemoryPercentage=$( echo "$nMemoryPercentage / 1" | bc )

if [ $nMemoryPercentage -le $nWarnMemoryUsage ] ; then
  echo "SUCCESS: Memory usage is [$nMemoryPercentage%]"
  echo ""
  echo "Warning limit=[$1%], Error limit=[$2%]"
  exit 0
fi
if [ $nMemoryPercentage -gt $nWarnMemoryUsage -a $nMemoryPercentage -le $nMaxMemoryUsage ] ; then
  echo "WARNING: Memory usage is [$nMemoryPercentage%]"
  echo ""
  echo "Warning limit=[$1%], Error limit=[$2%]"
  exit 2
fi
if [ $nMemoryPercentage -gt $nMaxMemoryUsage ] ; then
  echo "ERROR: Memory usage is [$nMemoryPercentage%]"
  echo ""
  echo "Warning limit=[$1%], Error limit=[$2%]"
  exit 1
fi