etc/resolv.conf-generate.bash: simple resolv.conf writer the way I want

etc/resolv.conf-generate.bash

@@ -0,0 +1,31 @@
+#!/usr/bin/env bash
+set -x
+
+# Require root or exit
+if [ "$(id -u)" != "0" ]; then
+	echo "This script requires root." 1>&2
+	exit 1
+fi
+
+# In case I am behind the /etc/resolv.conf, it's immutable and read-only,
+# which won't allow it to be rewritten.
+chattr -i /etc/resolv.conf
+chmod +w /etc/resolv.conf
+# Or it's a symlink to e.g. /run/systemd/resolve/stub-resolv.conf
+rm -v /etc/resolv.conf
+
+# Actual resolv.conf creation. OK, this could read resolv.conf in this
+# directory, but I like this being self-contained.
+# tee -p = operate in a more appropriate MODE with pipes.
+printf 'nameserver ::1\nnameserver 127.0.0.1\nnameserver 127.0.0.53\noptions edns0 trust-ad timeout:1 attempts:5\nsearch .\n' | tee -p /etc/resolv.conf
+
+# Remove all other permissions than everyone reading resolv.conf
+chmod a=r /etc/resolv.conf
+# Make resolv.conf immutable again so it's pretty sure nothing else edits it.
+chattr +i /etc/resolv.conf
+
+# Let's just see it's ok
+ls -l /etc/resolv.conf
+cat /etc/resolv.conf
+
+set +x