Call
<literal>A
</literal> the root file system. If
<citerefentry><refentrytitle>ls
</refentrytitle><manvolnum>1
</manvolnum></citerefentry> is used to view the contents of this directory, it will show two subdirectories,
<literal>A1
</literal> and
<literal>A2
</literal>. The directory tree looks like this: