我想使用 Popen 从我的 Python 脚本中调用 ImageMagick 的转换"实用程序，如下所示:
I'd like to call the "convert" utility from ImageMagick from my Python script using Popen, like so:
Popen(["convert", input_path, "-flop", output_file_path])
(上面的例子只是将图像水平反转)
(The above example simply reverses the image horizontally)
问题是当我在 Windows 中运行脚本时，它错误地调用了 Windows 附带的 convert.exe 实用程序将 FAT 分区转换为 NTFS！(位于Windowssystem32)
The problem is that when I run the script in Windows, it mistakenly calls the convert.exe utility that ships with Windows to convert FAT partitions to NTFS! (located in Windowssystem32)
现在，如果我在 system32 以外的任何目录中随机打开命令提示符并键入convert"，它会正确运行 ImageMagick 可执行文件.因此，这意味着 Popen 会自动在 system32 中查找.如何让它不在 system32 中查找，并运行正确的可执行文件?
Now, if I randomly open a command prompt at any directory other than system32, and type "convert", it correctly runs the ImageMagick executable. So, this implies that Popen is automatically looking in system32. How can I make it not look in system32, and run the correct executable?
搜索一个程序并非易事.我会明确指定 convert.exe 可执行文件的完整路径.
Search for a program is not trivial. I'd specify the full path to the convert.exe executable explicitly instead.
subprocess 使用 CreateProcess 在 system32 目录中查找，甚至在 %PATH% 中的任何其他目录之前:
subprocess uses CreateProcess on Windows that looks in system32 directory even before any other directory in %PATH%:
...如果文件名不包含扩展名，则附加.exe.因此，如果文件扩展名为.com，则该参数必须包括 .com 扩展名.如果文件名以句点 (.) 结尾没有扩展名，或者如果文件名包含路径，则 .exe 不是附加.如果文件名不包含目录路径，则系统按以下顺序搜索可执行文件:
... If the file name does not contain an extension,
.exeis appended. Therefore, if the file name extension is .com, this parameter must include the .com extension. If the file name ends in a period (.) with no extension, or if the file name contains a path, .exe is not appended. If the file name does not contain a directory path, the system searches for the executable file in the following sequence:
因此 convert 在这种情况下等同于 convert.exe.它首先查找包含 sys.executable 的目录，例如 C:Python27.然后在当前目录中:您启动 Python 脚本的位置.然后在 system32 中找到 convert.exe (文件系统实用程序，而不是 imagemagick).
Therefore convert is equivalent to convert.exe in this case. It first looks in a directory that contains sys.executable e.g., C:Python27. Then in the current directory: where you started the Python script from. Then in system32 where it finds convert.exe (filesystem utility, not imagemagick).
您可以尝试从 os.environ['PATH'] 中删除 system32 目录，它可能(?)禁止检查它:Popen(cmd, env=no_system32_environ)但它很脆弱(比显式路径更糟糕).
You could try to remove system32 directory from os.environ['PATH'] it may(?) suppress checking it: Popen(cmd, env=no_system32_environ) but it is fragile (worse than the explicit path).
在 Python 错误跟踪器上有一个相关问题:"子进程在 Windows 上选择了错误的可执行文件."
There is a related issue on Python bug tracker: "Subprocess picks the wrong executable on Windows."
cmd.exe(shell)使用不同的算法.请参阅Windows 如何定位在 shell 中输入的文件?
cmd.exe (the shell) uses different algorithm. See How does Windows locate files input in the shell?
如果你设置 shell=True 那么 convert 程序的搜索顺序:
If you set shell=True then the search sequence for convert program:
convert 不是内部 shell 命令convert is not an internal shell command%PATHEXT% 定义检查哪些文件扩展名以及检查顺序，例如 convert.com、convert.exe、convert.bat、convert.cmd if %PATHEXT% 是 .com;.exe;.bat;.cmd.
%PATHEXT% defines which file extensions are checked and in what order e.g., convert.com, convert.exe, convert.bat, convert.cmd if %PATHEXT% is .com;.exe;.bat;.cmd.
这篇关于以冲突的可执行文件/路径打开的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持跟版网！