tee stderr_如何使Tee仅在Linux中捕获stderr？

tee stderr

I would like to make tee catch the stderr and log it into a file.

我想让tee捕获stderr并将其记录到文件中。

A brute force method by let tee listen on both stderr and stdout is okay like

让tee在stderr和stdout上侦听的暴力方法是可以的

cmd 2>&1 | tee -a log

But how to make tee catch the stderr only?

但是如何使T恤只接住stderr？

You can make use of “process substitution” (>(...)) to creates a FIFO to catch the STDERR and pass it to tee.

您可以使用“进程替换”（ >(...) ）创建一个FIFO来捕获STDERR并将其传递给tee 。

Lets take an example t.sh:

让我们以t.sh为例：

#!/bin/bash

echo hello
1>&2 echo world

It works as expected:

它按预期工作：

$ ./t.sh 
hello
world
$ ./t.sh >/dev/null
world
$ ./t.sh 2>/dev/null
hello

Now, let’s redirect the STDERR to tee:

现在，让我们将STDERR重定向到tee ：

$ ./t.sh 2> >(tee /tmp/log)
hello
$ world
cat /tmp/log 
world

tee prints to STDOUT by default. Let’s make it print to STDERR:

tee 默认情况下打印到STDOUT。 让我们将其打印到STDERR：

$ ./t.sh 2> >(tee /tmp/log >&2)
hello
world
$ cat /tmp/log 
world

Verify it:

验证一下：

$ (./t.sh 2> >(tee /tmp/log >&2) ) >/dev/null
world

The “world” is not to the STDOUT anymore.

“世界”不再属于STDOUT。

翻译自: https://www.systutorials.com/how-to-make-tee-catch-the-stderr-only-in-linux/

tee stderr