.bat中的文件夹操作是否不稳定？

Question

我编写了一个.bat来自动生成和编译一个cmake项目。批处理文件

1. 可选rmdir build
2. 如果不存在mkdir build
3. cd build
4. cmake ..从上文件夹生成nmake项目
5. nmake编译项目

来文提交人：

@ECHO OFF
set "OpenCV_LIB=C:\Program Files (x86)\OpenCV2.1"
echo !! OpenCV Library: [ %OpenCV_LIB% ]
IF NOT EXIST "%OpenCV_LIB%" (
    echo Can't find OpenCV Library, please change OpenCV_LIB setting
    GOTO END
)

if %PROCESSOR_ARCHITECTURE%==x86   set BUILD_ARCH=x86
if %PROCESSOR_ARCHITECTURE%==AMD64 set BUILD_ARCH=x86_amd64
if %PROCESSOR_ARCHITECTURE%==IA64  set BUILD_ARCH=x86_IPF
echo !! Target architecture [ %BUILD_ARCH% ]
call "C:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\vcvarsall.bat" %BUILD_ARCH%

cd "sikuli-script"
set /p answer=Do you want to make clean first? (Y/N):
if %answer% == Y ( IF EXIST build rmdir /s /q build )
if %answer% == y ( IF EXIST build rmdir /s /q build )

IF NOT EXIST build mkdir build
cd build

IF NOT EXIST CMakeCache.txt ( cmake -G "NMake Makefiles" -D CMAKE_BUILD_TYPE=Release -D "OpenCV_DIR=%OpenCV_LIB%" .. )
nmake

:END
pause

在我一次又一次地运行这个.bat之后，我注意到有时cd build失败了，所以我修改了代码来测试它：

@ECHO ON
set /p answer=Do you want to make clean first? (Y/N):
if %answer% == Y ( IF EXIST build rmdir /s /q build )
if %answer% == y ( IF EXIST build rmdir /s /q build )
:DO_MKDIR_CD
IF NOT EXIST build mkdir build
cd build
if errorlevel 1 (
    pause
    GOTO DO_MKDIR_CD
)

结果表明，每次选择清除build时都会发生错误，甚至build的大小也很小(例如，在中断编译后，大小为3.08MB，183个文件，67个dirs)。

!! OpenCV Library: [ C:\Program Files (x86)\OpenCV2.1 ]
!! Target architecture [ x86_amd64 ]
Setting environment for using Microsoft Visual Studio 2010 x64 cross tools.

D:\repo\sikuli>cd "sikuli-script"

D:\repo\sikuli\sikuli-script>set /p answer=Do you want to make clean first? (Y/N):
Do you want to make clean first? (Y/N):y

D:\repo\sikuli\sikuli-script>if y == Y (IF EXIST build rmdir /s /q build  )

D:\repo\sikuli\sikuli-script>if y == y (IF EXIST build rmdir /s /q build  )

D:\repo\sikuli\sikuli-script>IF NOT EXIST build mkdir build

D:\repo\sikuli\sikuli-script>cd build
Access is denied.

D:\repo\sikuli\sikuli-script>if errorlevel 1 (
pause
 GOTO DO_MKDIR_CD
)
Press any key to continue . . .

因此，每次删除和重新创建build之后，cd build都会失败，然后cmake就会开始破坏我的源树。

错误检查和循环尝试可以解决这个问题，但是为什么文件系统不稳定？还是我写错了？

Answer 1

生成目录检查：

IF NOT EXIST build mkdir build

如果名为"build“的目录和文件都不存在，将创建该目录。

检查直接玩具存在的一种方法是：

if exist build\nul echo directory exist

如果要确保目录存在，请使用：

if not exist build\nul mkdir build

或更好：

if not exist build\nul (
  mkdir build
  if not exist build\nul (
    echo mkdir failed
    goto :eof
  )
)