#!/usr/bin/perl 

use strict;
use warnings;
my @data;
while(<DATA>) {
    my @row = split /,/,(/(.*)\n?/)[0]; # <-- nice and clear, right?
    shift(@row);
    push(@data,@row);
}
print join "\n", @data;
__DATA__
1,2,3,4
2,3,4,5
3,4,5,6