Persist DHCP provisioned IP config (Arch, systemd-networkd)

setup_net_arch.sh

#!/bin/bash

# Interface name, e.g., enp1s0
IFACE="enp1s0"

# Ensure systemd-networkd is enabled
systemctl enable systemd-networkd
systemctl start systemd-networkd

systemctl start systemd-resolved
systemctl enable systemd-resolved

# Get current IP, subnet mask (in CIDR notation), and gateway
IP=$(ip -4 addr show $IFACE | grep -oP '(?<=inet\s)\d+(\.\d+){3}/\d+')
GATEWAY=$(ip route | grep default | awk '/default/ { print $3 }')
DNS=$(awk '/^nameserver/ {print $2}' /etc/resolv.conf | tr '\n' ' ')

# Directory where systemd-networkd configurations are stored
NETWORKD_CONF_DIR="/etc/systemd/network"

# Create or overwrite the .network file for the interface
cat <<EOT > $NETWORKD_CONF_DIR/10-$IFACE.network
[Match]
Name=$IFACE

[Network]
Address=$IP
Gateway=$GATEWAY
DNS=$DNS
EOT

# Restart systemd-networkd to apply changes
systemctl restart systemd-networkd

echo "Static IP configuration for $IFACE is complete."