#!/usr/bin/perl
use warnings;
use strict;

my %pids;

my @to_be_processed = (1..20);

my $cmd = 'echo';

foreach my $p (@to_be_processed){ 
   $pids{$p}{'pid'} = open($pids{$p}{'fh'}, "$cmd $p 2>&1 |");
}

# get output dosn't work? get globs
foreach my $key(keys %pids){ 
   while (<{ $pids{$key}{'fh'} }>){print $_}
}


foreach my $key(keys %pids){
   waitpid($pids{$key}, 1);
}

print "done\n";