#! perl -slw
use strict;
use Time::HiRes qw[ sleep ];
use threads;
use threads::shared;

my @commands = map {
    my $t = 2+int( rand 5 );
    qq[ perl -E"sleep 1 while ++\$n < $t" ];
} 1 .. 300;


my $running :shared = 0;
my $done :shared = 0;
for my $cmd ( @commands ) {
    async{
        ++$running;
        system $cmd;
        --$running;
        ++$done;
    }->detach;
    printf( "\r$done, $running" ), sleep 0.1
        while $running > 2;
}
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