This is a non-destructive recursive version based on kyle's approach: 
sub unspace_keys {
  my $hash = shift;

  if (ref($hash) eq 'HASH') {
    my $out = {};
    for my $k (keys %$hash) {
      (my $k1 = $k) =~ s/\s+//g;
      $out->{$k1} = unspace_keys($hash->{$k});
    }
    return $out;
  } else {
    return $hash;
  }
}

my $new = unspace_keys( \%global );
print Dumper \%global;
print Dumper $new;

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In reply to Re: removing the spaces from keys of a complex hash by pc88mxer
in thread removing the spaces from keys of a complex hash by gwhite

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