wol_ubuntu.sh

#!/bin/sh -eu

BRD='10.255.255.255' # for searching interface

enable_wol() {
  sudo ethtool -s $1 wol g
  sudo sh -c 'cat << EOF > /etc/systemd/system/wol@.service
[Unit]
Description=Wake-on-LAN for %i
Requires=network.target
After=network.target

[Service]
ExecStart=ethtool -s %i wol g
Type=oneshot

[Install]
WantedBy=multi-user.target
EOF'
  sudo systemctl enable wol@$1
  echo "Enabled ($1)"
}

sudo apt update
sudo apt install -y ethtool

INTERFACE=`ip -o a | grep ${BRD} | cut -d' ' -f2`

[ "`sudo ethtool ${INTERFACE} | grep -oP '(?<=^\sWake-on:\s).'`" = 'g' \
      -a \
    -f '/etc/systemd/system/wol@.service' ] \
  && echo "Already set (${INTERFACE})" \
  || enable_wol ${INTERFACE}