Re: GNU Parallel Bug Reports tail follow with parallel

[Ole Tange]

On Wed, Aug 6, 2014 at 11:00 AM, Jaap Kroes <address@hidden> wrote:
> Hello,
>
> I have a problem using parallel with 'tail -f'. For example:
>
> seq 10 > test ; tail -f test | parallel -j2 'echo {}'
>
> This will not read to the end of the file, but to EOF-n lines, where n is
> the number of procs.
>
> Is this a bug in GNU-parallel?

>From the man-page:

       There is a a small issue when using GNU parallel as queue
       system/batch manager: You have to submit JobSlot number of jobs
       before they will start, and after that you can submit one at a time,
       and job will start immediately if free slots are available.  Output
       from the running or completed jobs are held back and will only be
       printed when JobSlots more jobs has been started (unless you use
       --ungroup or -u, in which case the output from the jobs are printed
       immediately).  E.g. if you have 10 jobslots then the output from the
       first completed job will only be printed when job 11 has started, and
       the output of second completed job will only be printed when job 12
       has started.

So the job is run; it is just the output that is delayed.


/Ole