my @match;
while (<>)) {
   my @caps = /pat/
      or next;
   @match = @caps;
}

if (@match) {
    print("Captured @match\n");
} else {
    die("No match\n");
}

##</code><code>##

my $match;
while (<>)) {
   $match = $_ if /pat/;
}

if (defined($match)) {
    print("Matched $match");
} else {
    die("No match\n");
}