Yeah, and all those concurrency controls of the shell suck. Here's a snippet to run N commands in parallel, wait for all of them, while supporting interrupting them with simple Ctrl+C:

    (
        trap 'kill 0' SIGINT;
        for i in {1..$N}
        do
            whatever_command $i &
        done
        wait
    )

The parentheses are absolutely crucial there for some reason, the { } won't give you pass-through of SIGINT. No wonder people keep re-inventing PID files, manually tracking $! and all kinds of other crazy bullshit that work 90% of the time, but sometimes fail to properly terminate the runaway children.

perhaps that's more an indictment of most programming languages