use strict;
use warnings;

my %file_hash;
my @lines = <DATA>;
    
for my $line (@lines)
{
    chomp($line);
    my ($name,$url,$text) = split('@',$line);
    $file_hash{$url} = $line unless ( $file_hash{$url} );
}

for my $key ( sort keys %file_hash )
{
    print "$file_hash{$key}\n";
}

__DATA__
name1@url1@text1
name1@url1@text1
name1@url1@text11
name2@url2@text2
name2@url2@text21
name3@url3@text3

##</code><code>##

col-uniq -d '@' -c 2  input.file > output.file