Code:
#!/usr/bin/perl
use strict;
my %seen=();
my @flds;
while (<DATA>){
chomp;
@flds=split /,/;
print $_,"\n" if !$seen{$flds[0]}++;
}
__DATA__
55,I,like,cookies,2,8,9
44,I,like,cookies,2,8,9
88,I,like,cookies,5,7,8
88,I,like,cookies,2,8,9
99,I,like,cookies,5,7,8
99,I,like,cookies,2,8,9
77,I,like,cookies,5,7,8
77,I,like,cookies,2,8,9
66,I,like,cookies,5,7,8
66,I,like,cookies,2,8,9
55,I,like,cookies,5,7,8
44,I,like,cookies,5,7,8