Thanks, that's a helpful one-liner.

Perl 5.8.0 gives the output you show, however, my older version (which is 5.004_04) gives:

$ /opt/perl5/bin/perl -MData::Dumper -we '%h={};$h{a}=1;print Dumper \
+%h'
Odd number of elements in hash list at -e line 1.
$VAR1 = {
          'a' => 1
        };
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