Add install shfmt script

install-scripts/.local/bin/install-shfmt

@@ -0,0 +1,22 @@
+#!/usr/bin/env bash
+
+# shellcheck disable=SC1090
+source "${XDG_DATA_HOME}/buddy-up/includes/utils.sh"
+
+get_arch () {
+    case $(uname -m) in
+        x86_64*)    echo amd64;;
+        *)          >&2 echo "unsupported architecture: $(uname -m)"; exit 1;;
+    esac
+}
+
+APP=shfmt
+VERSION=${VERSION:-3.3.1}
+DEST="${XDG_DATA_HOME}/apps/releases/${APP}"
+URL=https://github.com/mvdan/sh/releases/download/v${VERSION}/shfmt_v${VERSION}_$(get_os)_$(get_arch)
+
+mkdir_if_missing "${DEST}/${VERSION}"
+curl --silent --location --output "${DEST}/${VERSION}/${APP}" "${URL}"
+chmod 755 "${DEST}/${VERSION}/${APP}"
+set_current_link "${DEST}" "${VERSION}"
+set_link "${XDG_BIN_HOME}/${APP}" "${DEST}" "${APP}"