use warnings;
use strict;

while (<DATA>) {
    while (/\s*([\S]+\.xyz\.com)/g) {
        print "$1 \n";
    }
}

__DATA__
AAA-BBB-CCC aaa-bbb-ccc-2345.xyz.com aa-dg-hj hira.xyz.com
ddd-eee-fff-4567.xyz.com ddd-eee-fff vffg.xyz
sunil.xyz.com    mad.xyz.com
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