rpi systatus scrip

systatus.sh

#!/bin/bash

DELAY=5
PID_FILE=/tmp/systatus.pid
OUT_FILE=/tmp/systatus.json
RX_FILE=/sys/class/net/eth0/statistics/rx_bytes
TX_FILE=/sys/class/net/eth0/statistics/tx_bytes
TEMP_FILE=/sys/class/thermal/thermal_zone0/temp

if [ "stop" = "$1" ]; then
    [ -f $PID_FILE ] && kill -9 $(cat $PID_FILE)
    exit 0
fi

(while [ 1 ]; do
    rx0=$(cat $RX_FILE)
    tx0=$(cat $TX_FILE)
    sleep $DELAY
    rx1=$(cat $RX_FILE)
    tx1=$(cat $TX_FILE)
    if [ $rx0 -gt $rx1 ]; then
        rx1=$(($rx1 + 4294967295))
    fi
    if [ $tx0 -gt $tx1 ]; then
        tx1=$(($tx1 + 4294967295))
    fi
    mem=$(free | awk '/cache:/ {print $3/1024}')
    load=$(awk '{print $1}' /proc/loadavg)
    temp=$(awk '{print $1/1000}' $TEMP_FILE)
    #    $1     $2   $3   $4   $5   $6   $7    $8
    echo $DELAY $rx0 $rx1 $tx0 $tx1 $mem $load $temp | \
    awk '{printf("{\"rx\": %.2f, \"tx\": %.2f, \"mem\": %.2f, \"load\": %.2f, \"temp\": %.2f}",($3-$2)/1024/$1,($5-$4)/1024/$1,$6,$7,$8)}' >$OUT_FILE
done) >/dev/null 2>&1 &

echo $! >$PID_FILE