Shell Programming and Scripting

#!/usr/bin/perl

use strict;
use Net::SSH::Perl;

open (FH, "<hosts1") || die "cant open $!\n";


my @childs;

my $num = 5;

for (1 .. $num) {

while (<FH>) {


print "$_";

my $pid = fork();

if ($pid) {

push(@childs, $pid);
} 

elsif ($pid == 0) {
# child

chomp($_);

my $ssh = Net::SSH::Perl->new("$_", debug=>0);

$ssh->login("","");

my ($stdout,$stderr,$exit) = $ssh->cmd("hostname;date");

print $stdout;

sleep 5;

exit(0);

}

else {

die "couldn't fork: $!\n";

}

}

foreach my $k (@childs) {
waitpid($k, 0);

}

}

my $maxproc=3;
my $numproc=0;

for($n=0; $n<20; $n++)
{
        if(($pid=fork()) == 0)
        {
                system("sleep 10");
                exit 0;
        }

        push(@childs, $pid);
        $numproc++;

        while($numproc >= $maxproc)
        {
                waitpid(shift(@childs), 0);
                $numproc--;
        }
}

while($k=shift(@childs))
{
        waitpid($k, 0);
}