my @ptn_sortd = sort {    ${$partition_h{a}}{full_tabname}
                      cmp ${$partition_h{b}}{full_tabname}} @parnums;

##</code><code>##

Use of uninitialized value in string comparison (cmp) at ./<script name> line 156.
 at ./<script name> line 156.
Use of uninitialized value in string comparison (cmp) at ./<script name> line 156.
 at ./<script name>l line 156.
Use of uninitialized value in string comparison (cmp) at ./<script name> line 156.
 at ./<script name> line 156.
....

##</code><code>##

  grep {defined(${$partition_h{$_}}{full_tabname}) }