+# check the window size after each command and, if necessary,
+# update the values of LINES and COLUMNS.
+shopt -s checkwinsize
+# If set, the pattern "**" used in a pathname expansion context will
+# match all files and zero or more directories and subdirectories.
+#shopt -s globstar
+# for setting history length see HISTSIZE and HISTFILESIZE in bash(1)