log_db_1=`sqlplus -S dsg/dsg#123DSG << EOF
set heading off feedback off pagesize 0 verify off echo off numwidth 5;
select sequence# from v\\\$log where THREAD#=1 and status=‘CURRENT‘;
#注意点 \ 要转义
exit
EOF`
原文：http://www.cnblogs.com/snaid/p/4003354.html