BASH:错误消息未重定向到文件 [英] BASH: error message does not get redirected to file

问题描述

我有一个bash脚本，可以简单地调用不同的调用，并将stdout和stderr输出重定向到不同的文件.

I have a bash script that simply calls different calls and redirect stdout and stderr outputs to different files.

我已经做到了:

command 1> datafile 2>> errorfile

但是，如果命令错误(例如，错误的用户名和密码组合作为参数给出)，则错误消息不会重定向到错误文件.运行此脚本时，我仍然在屏幕上看到错误消息.例如，错误消息表明我提供的用户名和密码组合错误.

However, when the command is erroneous (e.g. wrong username and password combination given as arguments), the error message does not get redirected to the errorfile. I still see the error message on my screen when I run this script. For instance, the error message indicates that I provided a wrong combination of username and password.

我做错了什么? 我以为我应该在屏幕上看不到任何输出，因为我正在将stdout和stderr都重定向到文件.

What am I doing wrong? I thought I should see no output on screen because I'm redirecting both stdout and stderr to files.

推荐答案

也许程序不是在写stderr，而是直接打开/dev/tty与用户通信?在进行密码交互时，这种方法相当普遍:软件希望确保即使有任何重定向，密码提示也会通过"用户.

Perhaps the program isn't writing to stderr, but directly opening /dev/tty to communicate with the user? This approach is fairly common when it comes to password interaction: software wants to make sure password prompts get "through" to the user despite any redirections.

在这种情况下，您需要使用伪终端欺骗来安排输出以最终存储在文件中.

If this is the case, you need pseudo-terminal trickery to arrange output to end up in a file.

如果没有该软件的源代码，则可以使用strace/truss找出程序的实际作用.

If you don't have the source of the software, you can use strace/truss to find out what the program is really doing.

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