如何获取管道过程的退出代码？

Question

I wrote a small Go app that reads from stdin using the technique outlined here: https://flaviocopes.com/go-shell-pipes/

I invoke it like this: cmd | fsjl (where fsjl is my app)

Trouble is, the exit code is always 0 even when cmd exits 1.

How can I "forward" the exit code from cmd?

Here is my source code

Answer 1

That's not a job for your Go program. That's a job for whoever's managing the overall pipeline. Pipeline elements don't see each other's exit statuses.

For example, in bash, you can use pipefail:

If set, the return value of a pipeline is the value of the last (rightmost) command to exit with a non-zero status, or zero if all commands in the pipeline exit successfully. This option is disabled by default.

Here's an example, using a subshell to restrict the effects of pipefail to a single line:

(set -o pipefail && cmd | fsjl)

You can't always assume bash, but there are ways to do similar things in other shells.