download.service (/etc/systemd/system/download.service)

[Unit]
Description=Download packages
Wants=network-online.target
After=network-online.target

[Service]
User=root
Type=oneshot
ExecStart=/bin/pacman -Syuw --noconfirm

[Install]
WantedBy=multi-user.target

download.timer (/etc/systemd/system/download.timer)

[Unit]
Description=Run download.service hourly and on boot
Requires=download.service

[Timer]
Unit=download.service
OnBootSec=10s
OnUnitActiveSec=1h

[Install]
WantedBy=timers.target

Reload daemons and enable/start the timer

  1. systemctl daemon-reload
  2. systemctl enable download.timer
  3. systemctl start download.timer