This "perl" code:

connstr='user/password@DB';
$account='sqlplus -s $connstr <<END
...
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Has a few issues:

• connstr should be $connstr (Missing dollar sign), and preceding "my"
• Setting $account uses SINGLE QUOTES, which will not interpolate $connstr.
• Other variables inside the "heredoc" will not be interpolated either.
• The "heredoc" does not appear to be correctly formatted