diff --git a/bin/xpanes b/bin/xpanes
index 6960c3d..17bc684 100755
--- a/bin/xpanes
+++ b/bin/xpanes
@@ -511,19 +511,17 @@ xpns_log_filenames()  {
 # Return:
 #        Normalized <dirname>
 ## --------------------------------
+
 xpns_normalize_directory() {
-  local _dir="$1"
-  # Remove end of slash '/'
-  _dir="${_dir%/}"
+  # Remove end of slash '/' for the first arguement
+  local _dir="${1%/}"
   # tilde expansion
-  _dir="${_dir/#~/${HOME}}"
-  printf "%s\\n" "${_dir}"
+  printf "%s\\n" "${_dir/#~/$HOME}"
 }
-
 ## --------------------------------
 # Ensure existence of given directory
 # Usage:
-#        xpns_is_valid_directory <direname>
+#        xpns_is_valid_directory <dirname>
 # Return:
 #        Absolute path of the <dirname>
 ## --------------------------------
@@ -531,14 +529,13 @@ xpns_is_valid_directory() {
   local _dir="$1"
   local _checkfile="${XP_THIS_FILE_NAME}.$$"
   # Check directory.
-  if [[ ! -d "${_dir}" ]]; then
+  if ! [[ -d "${_dir}" ]]; then
     # Create directory
-    if mkdir "${_dir}"; then
-      xpns_msg_info "${_dir} is created."
-    else
+    if ! mkdir "${_dir}"; then
       xpns_msg_error "Failed to create ${_dir}"
       exit ${XP_ELOGDIR}
     fi
+    xpns_msg_info "${_dir} is created."
   fi
   # Try to create file.
   #   Not only checking directory permission,