file - How to redirect both stdout and stderr to file AND still output ONLY stderr?

Question

How can I redirect the output of a command such that both stdout and stderr gets logged in a file, AND I still want stderr to appear as output.

I also don't want to use bash for doing this. Is there such a way?

Answer 1

这很容易：

$ ( ./command.sh >> log ) 2>&1 | tee -a log

您将命令的标准输出写入log子外壳中的文件；比您将 stderr 写入管道；然后，我的方法是tee将其保存到 并将其log复制到控制台。

使用示例：

$ cat command.sh               
#!/bin/sh

echo out
echo err > /dev/stderr

$ ( ./command.sh >> log ) 2>&1 | tee -a log
err
$ cat log
out
err