popd [ +-n ]
          Removes entries from  the  directory  stack.   With  no
          arguments,  removes  the  top directory from the stack,
          and performs a cd to the new top  directory.   With  an
          argument  of the form +n, remove the nth entry counting
          from the left of the list shown by  the  dirs  command,
          starting with zero, and change to that directory.  With
          an argument of the form -n, remove the nth entry count-
          ing  from the right.  If the PUSHD_MINUS option is set,
          the meanings of + and - in this context are swapped.