最近工作中，需对数据进行比对。在此之前，则需将数据导出。想到以前用过的spool命令，实验一番，分享如下：
需建SQL执行脚本，内容如下：
set feedback off --关掉行数显示
set heading off --关掉标题行
set termout off --关掉终端显示
set echo off --关掉回显
set pagesize 0 --去掉头顶的空行
set trims on --去掉空字符
spool /home/oracle/test.txt
select * from dept;
spool off
执行该脚本，最后/home/oracle/test.txt显示的内容即为表dept的数据：
50 IT CHINA
10 ACCOUNTING NEW YORK
20 RESEARCH DALLAS
30 IT CHICAGO
40 OPERATIONS BOSTON
没有开头的SQL> select * from dept;和结尾的SQL> spool off
结合官档，总结一下SQL*Plus关于格式输出的命令：
SET ECHO {ON | OFF} Controls whether the START command lists each command in a script as the command is executed.
SET FEED[BACK] {6 | n | ON | OFF} Displays the number of records returned by a query when a query selects at least n records.
SET HEA[DING] {ON | OFF} Controls printing of column headings in reports.
SET LIN[ESIZE] {80 | n} Sets the total number of characters that SQL*Plus displays on one line before beginning a new line.
SET LONG {80 | n} Sets maximum width (in bytes) for displaying LONG, BLOB, BFILE, CLOB, NCLOB and XMLType values; and for copying LONG values.
SET PAGES[IZE] {14 | n} Sets the number of lines in each page.
SET TERM[OUT] {ON | OFF} Controls the display of output generated by commands executed from a script.
SET TI[ME] {ON | OFF} Controls the display of the current time.
SET TIMI[NG] {ON | OFF} Controls the display of timing statistics.
SET TRIMS[POOL] {ON | OFF} Determines whether SQL*Plus puts trailing blanks at the end of each spooled line.
SET TRIM[OUT] {ON | OFF} Determines whether SQL*Plus puts trailing blanks at the end of each displayed line.
SET VER[IFY] {ON | OFF} Controls whether SQL*Plus lists the text of a SQL statement or PL/SQL command before and after SQL*Plus
replaces substitution variables with values.
SET WRA[P] {ON | OFF} Controls whether SQL*Plus truncates the display of a SELECTed row if it is too long for the current line width
PS：关于SET ECHO语句，从定义上看有点费解，下面我们来看一下实验结果：
一、 SET ECHO OFF
1> 编辑SQL脚本t1.sql如下：
set echo off
select * from dept;
2> 执行该脚本
SQL> @t1.sql
DEPTNO DNAME LOC
---------- -------------- -------------
50 IT CHINA
10 ACCOUNTING NEW YORK
20 RESEARCH DALLAS
30 IT CHICAGO
40 OPERATIONS BOSTON
二、 SET ECHO ON
1> 编辑SQL脚本t1.sql如下：
set echo on
select * from dept;
2> 执行该脚本
SQL> @t1.sql
SQL> select * from dept;
DEPTNO DNAME LOC
---------- -------------- -------------
50 IT CHINA
10 ACCOUNTING NEW YORK
20 RESEARCH DALLAS
30 IT CHICAGO
40 OPERATIONS BOSTON
spool命令