r - 错误: 'dir' command not found while using System function in R

Question

我想在代码中使用R的System函数，因此我编写了简单的单行代码来检查其是否正常运行。这是我的一支类轮-

system("dir", intern = TRUE)

我正在使用Windows，因此它应该给我与命令提示符相同的输出(显示当前目录中存在的所有文件)。而是导致了错误:

Error in system("dir", intern = TRUE) : 'dir' not found

Answer 1

根据?system的描述:

command must be an executable (extensions ‘.exe’, ‘.com’) or a batch file (extensions ‘.cmd’ and ‘.bat’): these extensions are tried in turn if none is supplied. This means that redirection, pipes, DOS internal commands, ... cannot be used: see shell if you want to pass a shell command-line.

因此，不能使用DOS内部命令。它实际上不会为我返回任何错误，但它不会返回任何内容。

但是，shell可以按预期工作:

 shell('dir', intern = TRUE)
 #[1] " Volume in drive C is "                                                  
 #[2] " Volume Serial Number is "                                            
 #[3] ""                                                                              
 #[4] " Directory of C:\\Users\\TB\\Documents"                             
 #[5] ""                                                                              
 #[6] "07/06/2019  11:10    <DIR>          ."     
 #.....