+usage() {
+ cat <<EOF >&2
+
+$(basename "$0") [cmd]
+
+cmd | args | meaning
+----+-------+------------------------------------------------
+ f | | favorites
+ d | <dir> | from given dir
+ a | | all from $DIR_WALLPAPERS <- DEFAULT if no cmd.
+ h | | usage help. i.e. this message.
+----+-------+------------------------------------------------
+
+EOF
+}
+