zzz_main.sh: do more checks arround module list

lib/zzz_main_fct.sh

@@ -296,10 +296,16 @@ process_commandline_and_vars()
 
     # Check for module list existance and basic syntax
     if [[ -n $MODULE_LIST ]]; then
-        if [[ $(echo $MODULE_LIST | grep '-') ]]; then
+        for $mod in $MODULE_LIST; do
-            prnt E "Dash is forbidden in module name."
+            if [[ $mod =~ ['\"\'\ \\-!@#$%&*=+'] ]]; then
+                prnt E "The module \"$mod\" contains a forbidden character in its name."
                 die 5
             fi
+            if [[ ! -s "modules/$mod.sh" ]]; then
+                prnt E "The asked module \"$mod\", doesn't have any module file or module file is empty."
+                die 18
+            fi
+        done
     else
         prnt E "No module to execute!"
         die 5