批处理基础

基本语法
删除目录下所有文件

@ECHO OFF 
DEL . 
DR

列出文件列表输入到文件

@echo off
dir "C:Program Files" >b.txt
pause

设置变量SET

@echo off 
set message=Hello World 
echo %message%
pause

局部变量&全局变量，SETLOCAL 和ENDLOCAL之间包裹着局部变量

@echo off 
set globalvar=5
SETLOCAL               
set var=13145
set /A var=%var% + 5      /A 用在声明数字时
echo %var%
echo %globalvar%
ENDLOCAL

系统环境变量

@echo off 
echo %JAVA_HOME%

字符串

set message=Hello World  创建字符串
Set a=                             创建空字符串

检验字符串是否为空
@echo off 
SET a= 
SET b=Hello 
if [%a%]==[] echo "String A is empty" 
if [%b%]==[] echo "String B is empty "

字符串拼接
@echo off 
SET a=Hello 
SET b=World 
SET /A d=50 
SET c=%a% and %b% %d%
echo %c%
转变为数字类型
@echo off
set var=13145
set /A var=%var% + 5
echo %var%
取前五个字符
@echo off 
set str=Helloworld        
echo %str%                   Helloworld     
set str=%str:~0,5%       Hello
echo %str%

字符串替换
@echo off 
set str=Batch scripts is easy. It is really easy. 
echo %str% 
set str=%str:is=% 
echo %str%
去掉空格
@echo off 
set str=This string    has    a  lot  of spaces 
echo %str% 

set str=%str:=%      
echo %str%                   Thisstringhasalotofspaces