Add nfs_unmount script

nfs_unmount.sh

@@ -0,0 +1,30 @@
+#!/usr/bin/env bash
+
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+# Copyright 2022 Oliver "RealLarry" Jaksch
+
+# You can download the latest version of this script from:
+# https://github.com/MiSTer-devel/CIFS_MiSTer
+
+# Version 1.0 - 2023-03-10 - First commit
+
+#=========NO USER-SERVICEABLE PARTS BELOW THIS LINE=====
+
+if [ "$(id -u)" != "0" ]; then
+  echo "This script must be run as root. Please run again with sudo or as root user. Exiting."
+  exit 1
+else
+  umount -a -t nfs4
+fi