One-line install script

curl -fsSL https://git.redetzke.aero/Redetzke/GHOSTWIRE/raw/branch/main/install.sh | sh
downloads the latest release for the machine's architecture (Gitea, or
GitHub as fallback), checks it against SHA256SUMS and runs install with
the given arguments.

install.sh

@@ -0,0 +1,66 @@
+#!/bin/sh
+# Downloads the latest GHOSTWIRE release, checks it against SHA256SUMS and
+# runs its install command. Usage:
+#
+#   curl -fsSL https://git.redetzke.aero/Redetzke/GHOSTWIRE/raw/branch/main/install.sh | sh
+#   curl -fsSL …/install.sh | sh -s -- -y -domain vpn.example.net -email you@example.net
+#
+# Arguments are passed on to "GHOSTWIRE install". Everything is wrapped in
+# main so that a cut-off download runs nothing.
+set -eu
+
+GITEA=https://git.redetzke.aero/Redetzke/GHOSTWIRE
+GITEA_API=https://git.redetzke.aero/api/v1/repos/Redetzke/GHOSTWIRE/releases/latest
+GITHUB=https://github.com/danielredetzke/GHOSTWIRE
+GITHUB_API=https://api.github.com/repos/danielredetzke/GHOSTWIRE/releases/latest
+
+die() { echo "GHOSTWIRE: $*" >&2; exit 1; }
+
+latest() { curl -fsSL "$1" 2>/dev/null | sed -n 's/.*"tag_name": *"\([^"]*\)".*/\1/p'; }
+
+main() {
+	[ "$(uname -s)" = Linux ] || die "runs on Linux only"
+	case "$(uname -m)" in
+	x86_64 | amd64) arch=amd64 ;;
+	aarch64 | arm64) arch=arm64 ;;
+	armv7l | armv8l) arch=armv7 ;;
+	*) die "no build for $(uname -m)" ;;
+	esac
+	command -v curl >/dev/null || die "needs curl"
+	command -v sha256sum >/dev/null || die "needs sha256sum"
+
+	sudo=
+	if [ "$(id -u)" -ne 0 ]; then
+		command -v sudo >/dev/null || die "run as root or install sudo"
+		sudo=sudo
+	fi
+
+	# Gitea first, GitHub if it is not reachable.
+	repo=$GITEA
+	version=$(latest "$GITEA_API")
+	if [ -z "$version" ]; then
+		repo=$GITHUB
+		version=$(latest "$GITHUB_API")
+	fi
+	[ -n "$version" ] || die "could not find the latest release"
+
+	file=GHOSTWIRE-$version-linux-$arch
+	tmp=$(mktemp -d)
+	trap 'rm -rf "$tmp"' EXIT
+	echo "Downloading GHOSTWIRE $version ($arch) from $repo"
+	curl -fsSL -o "$tmp/$file" "$repo/releases/download/$version/$file"
+	curl -fsSL -o "$tmp/SHA256SUMS" "$repo/releases/download/$version/SHA256SUMS"
+	(cd "$tmp" && grep " $file\$" SHA256SUMS | sha256sum -c --status) ||
+		die "checksum of $file does not match SHA256SUMS"
+	mv "$tmp/$file" "$tmp/GHOSTWIRE"
+	chmod 755 "$tmp/GHOSTWIRE"
+
+	# The script itself arrives on stdin, so the questions read the terminal.
+	if [ -t 1 ] && [ -r /dev/tty ]; then
+		$sudo "$tmp/GHOSTWIRE" install "$@" </dev/tty
+	else
+		$sudo "$tmp/GHOSTWIRE" install "$@"
+	fi
+}
+
+main "$@"