run nethogs to watch network traffic

nethogs.service

[Unit]
Description=network usage by nethogs
After=network.target

[Service]
Type=simple
ExecStart=/home/shirou/nethogs.sh
Restart=always
RestartSec=5
StartLimitInterval=0
StartLimitBurst=5

# Logging
StandardOutput=append:/var/log/nethogs.log
StandardError=append:/var/log/nethogs.log

[Install]
WantedBy=multi-user.target

nethogs.sh

#!/usr/bin/env bash

/usr/sbin/nethogs -v 1 -d 10 -t wlan0 | grep -vi unknown