Oracle SQL Query to print Unix Timestamp

The actual query is available in http://jehiah.cz/a/oracle-date-to-unix-timestamp , but here is a slightly modified version which strips the decimal points and prints only the elapsed seconds.
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SELECT abs(to_number(((sysdate - to_date('01-JAN-1970','DD-MON-YYYY')) * (86400)))) as dt FROM dual;
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