systemd-udev-monitor.service
[Unit]
Description=udev Monitoring
DefaultDependencies=no
Wants=systemd-udevd.service
After=systemd-udevd-control.socket systemd-udevd-kernel.socket
Before=sysinit.target systemd-udev-trigger.service
[Service]
Type=simple
ExecStart=/bin/bash -c "/bin/udevadm monitor --udev | grep ' add' > /udev_monitor.log"
[Install]
WantedBy=sysinit.target