Hello -- GNU parallel is a great piece of software. I use it all the time.
>From time to time, I run into a file handle limit issue when I have many jobs to run (1M+): parallel: Warning: No more file handles. parallel: Warning: Raising ulimit -n or /etc/security/limits.conf may help. I hadn't realized that it was related to --keep-order, but Ole's comment on SO <https://stackoverflow.com/q/31343244/2320823> suggest's that it is. * What the relationship is between is between keep-order, the number of jobs, and the number of file handles used? Is there any relationship with the number of cores as well? [On some machines, I don't have control over the file limit, so better understanding this interplay would be useful] * Could someone also clarify the expected behavior on stdout? When multiple jobs (e.g. A and B) are running, is it possible for the output to become interleaved (without --keep-order)? In other words (each line represents output from job A or B), 1) Interleaved: A B A B A B 2a) Or am I guaranteed .... A A A B B B 2b) OR B B B A A A For my purposes, either 2a or 2b would be acceptable, but 1 would not. Do I need to specify --keep-order to guarantee 1 doesn't occur. Thanks for the help, Shyam PS. Ole, we just published a paper <http://www.jbc.org/content/early/2018/01/29/jbc.RA117.001052.short> that used GNU parallel. Of course, it is cited.
