Hash of array refs. Reads and print irrespective of the information is collective or not.

#!/usr/bin/perl -w
use strict;

my %hash;
(!/^$/) && (push @{$hash{(split /\s+/,$_)[0]}}, (split /\s+/,$_)[1]) w
+hile(<DATA>);

for my $key (keys %hash) {
    (print "$key\t$_\n" ) && ($key="") for (@{$hash{$key}}) ;
}
__DATA__
John     red
Mike     yellow
Peter    white
Peter    brown
Jim      purple
Antony   orange
Antony   green
George   black
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