for 循环中的批处理 SET /A 中断循环变量

Question

我有这个批处理脚本，它应该枚举目录中的所有文件：

SETLOCAL ENABLEEXTENSIONS ENABLEDELAYEDEXPANSION
SET /A cn=0
SET cwd=%~dp0

ECHO Files:
FOR %%I IN (%cwd%\*) DO (
    SET /A cn=cn+1
    ECHO !cn!
    IF "%%I"=="buthow" ()
    ECHO %%~nxI
)
EXIT /B 0

假设我们在文件夹中有文档d1.txt、d2.txt、d3.txt。上面的代码按预期工作，但是当我删除什么都不做的 if 语句（？）时，我得到以下输出：

1
d1.txt
2
cnd2.txt
3
cnd3.txt

这是为什么呢？

Answer 1

阅读if /?

Performs conditional processing in batch programs.

IF [NOT] ERRORLEVEL number command
IF [NOT] string1==string2 command
IF [NOT] EXIST filename command

  NOT               Specifies that Windows should carry out
                    the command only if the condition is false.

  ERRORLEVEL number Specifies a true condition if the last program run
                    returned an exit code equal to or greater than the number
                    specified.

  string1==string2  Specifies a true condition if the specified text strings
                    match.

  EXIST filename    Specifies a true condition if the specified filename
                    exists.

  command           Specifies the command to carry out if the condition is
                    met.  Command can be followed by ELSE command which
                    will execute the command after the ELSE keyword if the
                    specified condition is FALSE

The ELSE clause must occur on the same line as the command after the IF.

请注意，() 不是有效命令：

==> if 1==2 ()
) was unexpected at this time.

==> if 1==1 ()
) was unexpected at this time.

==> ()
) was unexpected at this time.

==>