$ ./11148698-00.pl
id  name
123 john
11  peter
87  helen

##</code><code>##

#!/usr/bin/env perl

use strict;
use warnings;
use utf8;

my @data = (
    q/id  name/,
    q/123 john/,
    q/34  john/,
    q/567 john/,
    q/11  peter/,
    q/899 peter/,
    q/87  helen/,
);

my %seen;
while ( my $str = shift @data ) {
    chomp $str;
    my @part = split /\s+/, $str, 2;
    if ( not exists $seen{ $part[1] } ) {
        print $str, qq{\n};
    }
    $seen{ $part[1] }++;
}
print qq{\n};