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

use Algorithm::Loops qw( NestedLoops );

my @items= ( 1..6 );
my $choose= 3;
my $iter= NestedLoops(
    [   [ 0..$#items ],
        ( sub { [ $_+1 .. $#items ] } ) x ($choose-1),
    ],
);
my @choice;
while(  @choice= @items[$iter->()]  ) {
    print "@choice\n";
    # replace above line with your code
}

##</code><code>##

1 2 3
1 2 4
1 2 5
1 2 6
1 3 4
1 3 5
1 3 6
1 4 5
1 4 6
1 5 6
2 3 4
2 3 5
2 3 6
2 4 5
2 4 6
2 5 6
3 4 5
3 4 6
3 5 6
4 5 6