Re: [Help-bash] Simple syntax nice a subprocess in a pipeline?

[Andy Chu]

I would solve this problem with a script like this:

fun1() { ... }

mypipeline() {
  fun1 | nice $0 fun2 | fun3
}

"$@"  # run function $1 with args $2 .. N (can also be made more explicit)

Then invoke it with "myscript.sh mypipeline"

I use the same pattern to run a shell function with xargs (or find
-exec), if you use that.

I've been meaning to write a blog post about this pattern for awhile.

It also solves the errexit problem, where failure is ignored when you
probably don't want it to be.  That is:

set -e
# using myfunc for its exit status, but internal failure is also ignored
if myfunc; then
  echo true
fi

# solves that problem
if $0 myfunc; then
  echo true
fi

Andy










On Mon, Jul 1, 2019 at 7:28 PM Peng Yu <address@hidden> wrote:
>
> Hi,
>
> I'd like to nice the process in which fun2 runs (fun2 is a bash
> function instead of an external command, so directly use `nice fun2`
> is not appropriate).
>
> fun1 | fun2 | fun3 ...
>
> I could get the PID in between the first "|" and the second "|", then
> renice that PID. But this is more cumbersome than the syntax of nicing
> an external program.
>
> Is there a convenient syntax to nice a subprocess in a pipeline? Thanks.
>
> --
> Regards,
> Peng
>