diff --git a/lib/functions.sh b/lib/functions.sh
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+
+##
+# return 0 (true) if array (passed by name) contains element 
+# usage: 
+#   ARRAY = ( a b c )
+#   containsElement ARRAY 'a' => 0
+containsElement () {
+	local -a 'arraykeys=("${!'"$1"'[@]}")'
+	for index in ${arraykeys[*]}; do 
+		current=$1"[$index]"
+		[[ "${!current}" == "$2" ]] && return 0; # found
+	done
+	return 1; # not found
+}
+
+##
+# 
+askConfirmation () {
+  case "$1" in
+    y|Y|yes|YES ) 
+      QUESTION="(Y/n)?"
+      DEFAULT=0
+      ;;
+    * ) 
+      QUESTION="(y/N)?"
+      DEFAULT=1
+      ;;
+  esac
+  read -p "$QUESTION : " choice
+  case "$choice" in 
+    y|Y|yes|YES ) return 0;; #true
+    n|no|N|NO ) return 1;; #false
+    * ) return $DEFAULT;;
+  esac  
+}
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