Bash set -x echo重定向以及命令 [英] Bash set -x echo redirects as well as commands

问题描述

我正在编写一个Bash脚本，我希望所有命令在发生时都得到回显.我知道我需要分别使用set -x和set +x来切换此行为(

I am writing a Bash script where I want all commands to be echoed as they occur. I know that I need to use set -x and set +x to toggle this behaviour off and on, respectively (SOF post here). However, it doesn't echo everything, namely, I/O redirects.

例如，假设我有一个非常简单的Bash脚本:

For example, let's say I have this very simple Bash script:

set -x
./command1 > output1
./command2 arg1 arg2 > output2

这将是输出

+ ./command1
+ ./command2 arg1 arg2

Bash没有将我的标准输出重定向到 output1 和 output2 .为什么是这样?我如何实现这种行为?也许我必须在脚本中设置一个shopt选项?

Bash is not echoing my stdout redirect to output1 and output2. Why is this? How can I achieve this behaviour? Perhaps is there a shopt option that I must set in the script?

注意::我还注意到管道将无法按预期打印.例如，如果我要使用以下命令:

NOTE: I also noticed that pipes will not print as expected. For example, if I were to use this command:

set -x
./command3 | tee output3

我将得到以下输出:

+ tee output3
+ ./command3

如何使命令完全按照编写命令的方式回显，而不是通过脚本对管道进行重新排序?

How do I make the commands be echoed exactly in the way they are written instead of having the pipe reordered by the script?

推荐答案

set -x不可能.您唯一的选择是通过DEBUG陷阱查看当前命令.

It isn't possible with set -x. Your only option is to view the current command through a DEBUG trap.

trap 'printf %s\\n "$BASH_COMMAND" >&2' DEBUG

这不会像set -x那样显示精确的参数.合并它们应该可以给您提供完整的画面，尽管它有很多调试输出.

This won't show the precise arguments as set -x will. Combining them should give you the full picture, though it's a lot of debug output.

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