xargs equivalent in perl - perl

Question

I liked to make something, what xargs in shellscripting does. Thus:
Running external commands by the exec() system calls
as child processes
parallel
waiting their execution (ideally with a timeout)
How can it be done in perl?

Answer 1

You could use the Proc::Background module.
Particularly interesting is the sub timeout_system(..).
Here's an example coming from the Proc::Background module page:
use Proc::Background;
timeout_system($seconds, $command, $arg1);
timeout_system($seconds, "$command $arg1");
my $proc1 = Proc::Background->new($command, $arg1, $arg2);
my $proc2 = Proc::Background->new("$command $arg1 1>&2");
$proc1->alive;
$proc1->die;
$proc1->wait;
my $time1 = $proc1->start_time;
my $time2 = $proc1->end_time;
# Add an option to kill the process with die when the variable is
# DETROYed.
my $opts = {'die_upon_destroy' => 1};
my $proc3 = Proc::Background->new($opts, $command, $arg1, $arg2);
$proc3 = undef;

Answer 2

my #join;
push #join, fasync {
local $SIG{ALRM} = sub { die "alarm\n" };
alarm 10;
# exec(..);
sleep 20;
print "job1\n";
};
push #join, fasync {
print "job2\n";
};
# wait for jobs
$_->() for #join;
sub fasync(&) {
my ($worker) = #_;
my $pid = fork() // die "can't fork!";
if ($pid == 0) {
$worker->();
exit(0);
}
return sub {
my ($flags) = #_;
return waitpid($pid, $flags // 0);
}
}