Re: kill the LHS command of a pipe once the RHS command terminates

[Vincent Lefevre <vincent@xxxxxxxxxx>]

On 2019-06-29 16:30:55 +0100, Stephane Chazelas wrote:
> 2019-06-29 03:24:33 +0200, Vincent Lefevre:
> [...]
> > Thus if the left-hand-side process has terminated, this tries to
> > kill a random process!
> [...]
> 
> Fair enough.
> 
> Then, how about:
> 
> page-and-kill() ("$@" | { ${PAGER:-less}; kill -s PIPE 0; })

Unfortunately, this is not usable as a Ctrl-C kills the pager.
Actually I suppose that Ctrl-C kills the subshell, and the pager
as a consequence. And if I use the following,

page-and-kill() (trap '' INT; "$@" | { trap - INT; less; kill 0; })

the "kill 0" no longer kills the command. This can be seen with:

(trap '' INT; { echo foo; sleep 10; } | { trap - INT; less; kill 0; })

after typing Ctrl-C in "less", then q to quit. I've noticed that
dash and mksh have the same issue, but neither bash, nor ksh93.

-- 
Vincent Lefèvre <vincent@xxxxxxxxxx> - Web: <https://www.vinc17.net/>
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Work: CR INRIA - computer arithmetic / AriC project (LIP, ENS-Lyon)