Check number of arguments when installing to microsd

src/freedombone-prep

@@ -20,6 +20,9 @@
 # You should have received a copy of the GNU General Public License
 # along with this program. If not, see <http://www.gnu.org/licenses/>.
 
+# The number of arguments
+NO_OF_ARGS=$#
+
 # Version number of this script
 VERSION="1.00"
 
@@ -45,8 +48,16 @@ function show_help {
     echo ''
     echo 'freedombone-prep -d [microSD device] --ip [BBB LAN IP address] --iprouter [Router LAN IP address]'
     echo ''
+    echo 'See the manpage for more details'
+    echo ''
 }
 
+# if no arguments are given
+if [[ $NO_OF_ARGS == 0 ]]; then
+  show_help
+  exit 0
+fi
+
 while [[ $# > 1 ]]
 do
 key="$1"