On Fri, Oct 3, 2008 at 4:13 AM, Jan Schampera <[EMAIL PROTECTED]> wrote: > Mike Coleman wrote: >> >> Here's a bash feature I'd love to see, but don't have time to >> implement myself: a "--free-slot" flag to 'wait' that will wait until >> there is at least one free "slot" available, where a slot is basically >> a CPU core. >> >> Example usage: >> >> $ for ((n=0; n<100; n++)); do >> my_experiment $n > $n.out & >> wait --free-slot 4 >> done >> >> which I would run on a quad-CPU host. The meaning of the wait is: if >> I already have four background invocations of "my_experiment" running, >> wait until one finishes, then proceed. (If there are fewer than four >> running, proceed immediately.) >> >> This provides a nice sloppy way of letting me parallelize in a script >> without having to complicate things. "make -j" and "xargs -P" provide >> some of this capability, but are a lot more work to set up--I'd really >> like to have this at my fingertips for interactive stuff. > > I did something like that as a script, using an array of PIDs and a big loop > and so on. I don't think it needs to be part of internal Bash features, it > wasn't that much work.
I'm sure this could be done with a script, but I'm imagining a scenario like the above where I don't need to get out an editor or anything--it'd be a quick-and-dirty thing I could type in at the command line. If there's a way to write "wait-free-slot" as a function (that could be source'd in), I'm all ears, but I don't see it. I guess it could poll the current children with ps, but that seems kind of ugly. Mike
