从FileUtils获取执行的命令？

问题描述

当您将：verbose 标志传递给FileUtils命令时，该命令会打印到STDOUT。是否有一种方法可以捕获该命令，以便可以在其他地方记录或使用它？ 如果您查看 FileUtils 它使用以下方法来完成它的详细输出：

  def fu_output_message （msg）＃：nodoc：
 @fileutils_output || = $ stderr 
 @fileutils_label || =''
 @ fileutils_output.puts @fileutils_label + msg 
结束
  

即它将消息写入 @fileutils_output ，默认情况下它使用 $ stderr 。似乎没有方法可以改变 @fileutils_output ，但您可以添加一个：

  module FileUtils 
 def FileUtils.fileutils_output =（new_out）
 @fileutils_output = new_out 
 end 
 end 
  

然后，如果您想将命令捕获到文件中，您可以这样做：

  my_fu_log = open（'fu_log.log'，'w'）
 FileUtils.fileutils_output = my_fu_log 
＃FileUtils操作：verbose => true here 
 my_fu_log.close 
 FileUtils.fileutils_output = $ stderr＃如果要
  

$，则还原写入到stderr b $ b

或者如果你想让它们在一个字符串中，你可以这样做：

  log = StringIO.new 
 FileUtils.fileutils_output = log 
＃FileUtils操作：verbose => true在这里
＃命令在log.string 
  

另外，还有一个模块 FileUtils :: Verbose 它基本上包含 FileUtils （所有方法都一样），但默认选项为：verbose => true ，所以如果你想捕获很多命令，你可以使用它而不是每次指定选项。 （您需要像上面一样将 fileutils_output = 方法添加到此模块中。）

替代品

作为在下面的评论中说，另一种方法是重新分配 $ stderr ，但正如他所说的，这意味着所有写入stderr的东西（不仅仅是 FileUtils ）被重定向。如果所有的 FileUtils 操作都是一次性发生而没有其他任何东西，那么这可能不是问题。所以，我们有以下几点：

  orig_stderr = $ stderr＃保留原始stderr的引用
 $ stderr = my_fu_log 
＃在这里使用FileUtils 
 $ stderr = orig_stderr＃restore stderr 
  

最后，你如果您需要更多的控制，可以重新打开 FileUtils 并覆盖 fu_output_message（msg）本身。

When you pass the :verbose flag to a FileUtils command, the command gets printed to STDOUT. Is there a way to capture the command so it can be logged or used elsewhere?

解决方案

If you look at the source for FileUtils it uses the following method for doing its verbose output:

def fu_output_message(msg)   #:nodoc:
  @fileutils_output ||= $stderr
  @fileutils_label  ||= ''
  @fileutils_output.puts @fileutils_label + msg
end

i.e. it is writing the messages to @fileutils_output and by default it is using $stderr. There doesn't seem to be a method to alter @fileutils_output but you could add one:

module FileUtils
  def FileUtils.fileutils_output=(new_out)
    @fileutils_output = new_out
  end
end

Then if you wanted to capture the commands into a file you could do:

my_fu_log = open('fu_log.log', 'w')
FileUtils.fileutils_output = my_fu_log
# FileUtils operations with :verbose => true here
my_fu_log.close
FileUtils.fileutils_output = $stderr # restore writing to stderr if you want

or if you wanted to get them in a string you could do:

log = StringIO.new
FileUtils.fileutils_output = log
# FileUtils operations with :verbose => true here
# commands are in log.string 

Also, there is a module FileUtils::Verbose which basically includes FileUtils (so has all the same methods) but defaults the options to :verbose => true so if you wanted to capture lots of commands you could use this instead of specifying the option each time. (you would need to add the fileutils_output= method to this module in the same way as above.)

Alternatives

As Joshua says in the comments below, an alternative is to reassign $stderr but as he says this does mean that everything written to stderr (not just by FileUtils) is redirected. If all the FileUtils operations are happening in one go without anything else in between then this might not be an issue. So something along the lines of:

orig_stderr = $stderr # keep reference to original stderr
$stderr = my_fu_log
# use FileUtils here
$stderr = orig_stderr # restore stderr

Finally, you could reopen FileUtils and override fu_output_message(msg) itself if you need more control.

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