Today I wrote my first service file for arch! It's so easy!...
Before today I connected to the internet by executing
################################
ip link set enp2s0 up
pppoe-start
################################
at start up of xfce. How inelegant!
By just following instructions on the wiki I created easily my own service file:
################################
[Unit]
Description=Network Connectivity
Wants=network.target
Before=network.target
BindsTo=sys-subsystem-net-devices-enp2s0.device
After=sys-subsystem-net-devices-enp2s0.device
[Service]
Type=oneshot
RemainAfterExit=yes
ExecStart=/sbin/ip link set enp2s0 up
ExecStart=/usr/sbin/pppoe-start
ExecStop=/usr/sbin/pppoe-stop
ExecStop=/sbin/ip link set enp2s0 down
[Install]
WantedBy=multi-user.target
################################
systemctl can now start and stop the service, or enable it on boot!