Add script for advanced usage blog post

tools/netTraffic.sh

@@ -0,0 +1,43 @@
+#!/bin/bash
+##
+##This script return the bandwidth in Rx and Tx by substract old Rx/Tx values by the new ones.
+##Ex: If the script is called every 10s, it will compare the rx_bytes 10s ago (old_rx) with the new one (rx) and substract these two values to get a value as Bytes/10S
+##
+## Author : TDUVAL
+
+# Location of the networkTraffic files
+LOCATION="/usr/share/rpimonitor/web/custom/net_traffic/"
+
+# Test if directory $path exist then create it
+if [ ! -d $LOCATION ]
+then    mkdir $LOCATION
+fi
+
+# Test if file rx exist then create it
+if [ ! -f $LOCATION/rx ]
+then    touch $LOCATION/rx
+fi
+
+# Test if file tx exist then create it
+if [ ! -f $LOCATION/tx ]
+then    touch $LOCATION/tx
+fi
+
+# Get old values in rx/tx files
+OLDRX=`cat $LOCATION/rx`
+OLDTX=`cat $LOCATION/tx`
+
+# Get new values
+RX=`cat /sys/class/net/eth0/statistics/rx_bytes`
+TX=`cat /sys/class/net/eth0/statistics/tx_bytes`
+
+# Store new values in rx/tx files
+echo $RX > $LOCATION/rx
+echo $TX > $LOCATION/tx
+
+# Substract new - old to get traffic in Bytes/period
+RX_TRAFFIC=$(($RX-$OLDRX))
+TX_TRAFFIC=$(($TX-$OLDTX))
+
+# Display traffic value in stdout
+echo -e "rx=$RX_TRAFFIC\ntx=$TX_TRAFFIC"