use strict;
use warnings;

my $cmd_1 = "perl hello.pl";

open (CMD, "$cmd_1 2>&1|") or warn ("!!! Can't run program: $!\n");

while (my $line = <CMD>)
{
	print $line;
        #if ($line =~ m/^xyz/)
        #{
        #   # do some string manipulation and write it to another file
	#}
}
close CMD;

##</code><code>##

use strict;
use warnings;

$| = 1;

print "Hello World\n";
print "Sleeping 1000 seconds\n";

for (1 .. 1000) {
    sleep 1;
    print ".\n";
}