Xubuntu 14.04 xrdp disconnected session cleanup script

#!/bin/bash

# This script cleans up disconnected xrdp+Xvnc sessions to free up memory
# Xvnc processes with no established connections are assumed inactive and terminated
# Running this script periodically will clean up remaining sessions as users disconnect

echo "`date +\"%d.%m.%Y %T\"` xrdp session cleanup script running"

XVNC_CONN=`netstat -ap --numeric-ports | grep -E "(tcp|udp)" | grep Xvnc`
ALL_SESSIONS=`printf '%s\n' "${XVNC_CONN[@]}" | grep LISTEN`
ACT_SESSIONS=`printf '%s\n' "${XVNC_CONN[@]}" | grep ESTABLISHED`

# Extract PIDs for all Xvnc processes that are listening
IFS=$'\n'
for i in ${ALL_SESSIONS[@]}; do
#       echo $i
        [[ "$i" =~ [0-9]+/Xvnc ]] && [[ "$BASH_REMATCH" =~ [0-9]+ ]] && PID=$BASH_REMATCH
#       echo $PID
        PIDS+=("$PID")
        ACTIVE[$PID]='0'
#       echo ${ACTIVE[$PID]}
#       echo
done

# Extract PIDs for Xvnc processes with established connections, mark as active
for i in ${ACT_SESSIONS[@]}; do
        [[ "$i" =~ [0-9]+/Xvnc ]] && [[ "$BASH_REMATCH" =~ [0-9]+ ]] && PID=$BASH_REMATCH
#       echo $PID
        ACTIVE[$PID]='1'
done

# Kill all inactive Xvnc processes to free memory
for i in ${PIDS[@]}; do
        [[ "${ACTIVE[$i]}" == "1" ]] && echo "PID $i is active"
        [[ "${ACTIVE[$i]}" == "0" ]] && echo "PID $i has no active connections, killing" && kill $i
done