Re: "builtin jobs" does not output to stdout.

[Robert Elz]

    Date:        Sat, 11 Feb 2023 22:54:47 +0900
    From:        =?UTF-8?B?5bKh6YOo5bCG5bm4?= <okabe_m@hmi.aitech.ac.jp>
    Message-ID:  
<CADE-OTFYU3av0YAn=XTa4hUx53SC8Ss_HE9JQ7b4fB=xTN+EFw@mail.gmail.com>

  | "jobs" outputs to stdout, but "builtin jobs" does not
  | output to stdout.

Your test is flawed.   Processes in a pipeline are in a
subshell environment.  That environment has no jobs, hence
no output.

But there is a special exemption for that, when 'jobs'
is the first command in the subshell.  Then it reports
its parent's jobs table instead (this is to allow
j=$(jobs) to work mainly).

So jobs|whatever produces output, but builtin jobs|... does not.

To test whether builtin jobs writes to stdout, use

        builtin jobs >/tmp/foo

instead.   No subshell there, so it should work.


Why would you want to ever say "builtin jobs" though?
The jobs command has to be buikt in to work.

kre