popd [ {+|-}n ]
       Removes a entry from the directory stack, and  per-
       form  a  cd to the new top directory. With no argu-
       ment, the current top entry is removed.   An  argu-
       ment  of  the form `+n' identifies a stack entry by
       counting from the left of the  list  shown  by  the
       dirs  command,  starting with zero.  An argument of
       the  form  -n  counts  from  the  right.   If   the
       PUSHD MINUS  option is set, the meanings of `+' and
       `-' in this context are swapped.
