jobs built-in command and PROMPT_COMMAND

[Christoph Anton Mitterer]

Hey.

Two things come together here:
a) In my PS1, I display the number of background jobs (\j), but only
when there are any.
So I have more or less something like:
PS1='...$( [ -n "$(jobs)"] && printf '\j')...'


b) Every now and then it happens that I accidentally Ctrl-D to
fast/often, while there are still some stopped background vi or so
running, killing them.

AFAICS, there is no direct way in bash to prevent this (it would be
nice if there was a feature, that ignores Ctrl-D, but *only* when there
are running jobs).

As a workaround I'd do something like:
        protect_background_jobs()
        {
            if [ -n "$(jobs)" ]; then
                IGNOREEOF=100
            else
                unset -v IGNOREEOF
            fi
        }
        PROMPT_COMMAND=protect_background_jobs

which in principle works, but... (see below).



feature requests with respect to (a):
- the filter parameters -r and -s for the jobs built-in:
  It would be nice if these could be use in combination (right now the
  latter overrides the former)
  The reason is that there seems to be a 3rd class of jobs that jobs
  prints, namely the "Done" jobs.
  Specifying both, -r and -s would then have the effect of showing any
  running/stopped but no done jobs.
  These done jobs show up once in my above prompt as "0". Of course 
  there are workarounds to that, but these seem a bit ugly.

- consequentially it would be nice to have an additional -d or so,
  which prints just any done jobs.

- it would be nice if there were additional symbols to \j like,
  \j{s|r|d}, so that one can easily print the running/stopped bg jobs
  separately, without having to do ugly $(jobs -r | wc -l) stuff



with respect to (b):
- (b) kinda breaks (a), cause it seems that when PS1 is evaluated, the
  command from (b) somehow still counts as background job that has just
  been Done, so $(jobs) gets never empty. Of course one can work around
  that, too, but again, makes it a bit messier.

  Is that desired or some bug?



Cheers,
Chris.