R系统函数总是返回错误127 [英] R system functions always returns error 127

问题描述

我需要从 R 执行外部工具，并在该工具中处理错误（如果有）。
我知道3个功能来做一些熟悉我的任务的事情：

I need to execute external tool from R and process errors (if any) occurred in that tool. I know 3 functions to do something familiar with my task:

shell, system and system2.

为了测试这些，我看到这个命令

Thying to test those, I see that command

shell("notepad") 

打开记事本。据我所知，shell不允许检查错误（没有接口可以查看stderr）。

opens notepad. As far as I know shell doesn't allow to check errors (there's no interface to look into stderr).

当我调用

system("notepad")

或

system2("notepad") 

R 冻结试图做出这些命令。

R freezes trying to make those commands.

致电

system("start notepad") 

或

system2("start notepad") 

返回警告

Warning message:
running command '"start notepad"' had status 127 

推荐答案

正如我在评论中提到的那样，R文档显示，在Windows中， system（）函数不会启动单独的shell（如果需要）。这就是为什么命令行命令以 system（）运行，但需要单独窗口的记事本不会运行：

As I mentioned in my comments, the R documentation reveals that in Windows the system() function does not launch a separate shell (if needed). This is why command line commands run with system(), but Notepad, which needs a separate window, does not run:

从文档对于 system（）：

最重要的区别是在Unix-同样的系统启动一个shell然后运行命令。在Windows上，该命令直接运行 - 使用shell通过shell运行命令（默认情况下，Windows shell cmd.exe与POSIX shell有很多不同）。

The most important difference is that on a Unix-alike system launches a shell which then runs command. On Windows the command is run directly – use shell for an interface which runs command via a shell (by default the Windows shell cmd.exe, which has many differences from a POSIX shell).

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