最简单的解决方案，由两行代码组成:

SET /A var02 = %var01% / 1
IF %ERRORLEVEL% NEQ 0 (ECHO Variable var01 is NOT EXIST)

从IF /?：

如果命令扩展是启用If 变更如下: IF [/I] string1 compare-op string2命令 IF CMDEXTVERSION编号命令 IF定义变量命令 ．．．．．． DEFINED条件刚好 像EXISTS一样，除了它需要一个 环境变量名称和返回值 如果环境变量为，则为 定义的。

你可以使用:

IF "%~1" == "" GOTO MyLabel

去掉外部的引号。一般来说，这是一种比使用方括号更可靠的方法，因为即使变量中有空格，它也能工作。

This way looks correct:

if "%~1" == "" if [%1] == [] echo Argument 1 is really empty.

First filter (if "%~1" == "") из safe way to detect argument is empty or "".
Second filter (if [%1] == []) will skip "" argument.
Remember we have two kind of empty arguments : really empty (nothing) and empty quotes "".
We have to detect both.

Next code takes all arguments "as is" in variable args:

:GetArgs
set args=%1
:ParseArgs
shift /1
if "%~1" == "" if [%1] == [] goto :DoneArgs
set args=%args% %1
goto :ParseArgs
:DoneArgs
if not defined args echo No arguments
if defined args echo Aguments are: %args%

This code correctly process "normal" arguments (simple words, "multiword phrases" or "") with balanced quotes.
Quoted arguments can even contain special chars like "a & b".
But it is still can fail with "abnormal" expressions with unbalanced quotes (do not use them).

使用!而不是“空字符串检查”

@echo off
SET a=
SET b=Hello
IF !%a%! == !! echo String a is empty
IF !%b%! == !! echo String b is empty

你可以使用

if defined (variable) echo That's defined!
if not defined (variable) echo Nope. Undefined.