diff --git a/conf/include_functions.conf b/conf/include_functions.conf
index 8c82067..9f563da 100644
--- a/conf/include_functions.conf
+++ b/conf/include_functions.conf
@@ -65,4 +65,20 @@ containsElement () {
    return 1
 }
 
+is_number() {
+
+   return $(test ! -z "${1##*[!0-9]*}" > /dev/null 2>&1);
+
+   # - also possible
+   # -
+   #[[ ! -z "${1##*[!0-9]*}" ]] && return 0 || return 1
+   #return $([[ ! -z "${1##*[!0-9]*}" ]])
+}
+
+trim() {
+    local var="$*"
+    var="${var#"${var%%[![:space:]]*}"}"   # remove leading whitespace characters
+    var="${var%"${var##*[![:space:]]}"}"   # remove trailing whitespace characters
+    echo -n "$var"
+}