bug#70219: Bug/Issue with timeout and signals

[Chris Elvidge]

On 05/04/2024 at 16:19, Branden R. Williams via GNU coreutils Bug 
Reports wrote:
> I was integrating the timeout command into a shell script and realized the manpage 
> & the --help docs do not accurately describe how the tool works. In addition, 
> there appears to be a bug related to arguments passed. I am running version 9.1.
>
> According to the help screen, this command should work:
>
>         timeout -k 10s ping example.com <http://example.com/>
>
> It fails, however, because the next argument after invoking -k is the kill 
> signal you want to send. The command (to send a SIGKILL) must be:

As I understand it, the argument after -k (or --kill-after=) is the time 
to wait and send the kill signal if the timeout fails.
So this line:

>         timeout -k 9 10s ping example.com <http://example.com/>

sends a kill signal 9 seconds after the timeout, if the timeout hasn't 
worked.

The -s option is to change the signal sent (as below).

> I believe the kill after functionality and docs should be modified to send a 
> default signal of SIGTERM without an additional argument so the first iteration 
> above would work. Then you could explain that if you wanted to send a DIFFERENT 
> signal, use the -s flag that is there to pass one. But according to the docs, 
> the first command SHOULD work. Even using the --kill-after= syntax passes in 
> the kill signal into that argument, not the actual time.
>
> Thank you for your consideration and for maintaining such a critical set of 
> tools!
>
> Regards,
>
> B


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Chris Elvidge