linux - 如何使用Bash将stdout和stderr重定向并附加到文件？(How to redirect and append both stdout and stderr to a file with Bash?)

Question

To redirect stdout to a truncated file in Bash, I know to use:

(要将stdout重定向到Bash中的截断文件，我知道使用：)

cmd > file.txt

To redirect stdout in Bash, appending to a file, I know to use:

(为了重定向Bash中的stdout ，将其附加到文件中，我知道要使用：)

cmd >> file.txt

To redirect both stdout and stderr to a truncated file, I know to use:

(要将stdout和stderr都重定向到截断的文件，我知道使用：)

cmd &> file.txt

How do I redirect both stdout and stderr appending to a file?

(如何将stdout和stderr都重定向到文件？)

cmd &>> file.txt did not work for me.

(cmd &>> file.txt对我不起作用。)

  ask by flybywire translate from so

Answer 1

cmd >>file.txt 2>&1

Bash executes the redirects from left to right as follows:

(Bash执行从左到右的重定向，如下所示：)

1. >>file.txt : Open file.txt in append mode and redirect stdout there.

   (>>file.txt ：以附加模式打开file.txt在那里重定向stdout 。)

2. 2>&1 : Redirect stderr to "where stdout is currently going" .

   (2>&1 ：将stderr重定向到“ stdout当前所在的位置” 。)

   In this case, that is a file opened in append mode.

   (在这种情况下，这是在附加模式下打开的文件。)

   In other words, the &1 reuses the file descriptor which stdout currently uses.

   (换句话说， &1重用了stdout当前使用的文件描述符。)