Override $WORKING_DIR variable

First, use value of $GETSSL_HOME variable if exists
Second, use value of $XDG_CONFIG_HOME variable if exists
Third, use $HOME/.config directory if exists
Last, use default directory ~/.getssl as WORKING_DIR

Some Links
FreeDesktop - https://specifications.freedesktop.org/basedir-spec/basedir-spec-latest.html
ArchLinux - https://wiki.archlinux.org/index.php/XDG_Base_Directory_support

getssl

@@ -1483,6 +1483,21 @@ if [[ -z "$DOMAIN" ]] && [[ ${_CHECK_ALL} -ne 1 ]]; then
   graceful_exit
 fi
 
+# if exist the ~/.config directory, use it as parent directory
+if [[ -d "${HOME}/.config" ]]; then
+  WORKING_DIR="${HOME}/.config/getssl"
+fi
+
+#if set $XDG_CONFIG_HOME environment variable, use it as parent directory
+if [[ ! -z ${XDG_CONFIG_HOME+x} ]]; then
+  WORKING_DIR="${XDG_CONFIG_HOME}/getssl"
+fi
+
+# if set $GETSSL_HOME enviroment variable, use it as parent directory
+if [[ ! -z ${GETSSL_HOME+x} ]]; then
+  WORKING_DIR="${GETSSL_HOME}"
+fi
+
 # if the "working directory" doesn't exist, then create it.
 if [[ ! -d "$WORKING_DIR" ]]; then
   debug "Making working directory - $WORKING_DIR"