Find All Possible Combination of Features (Column) in a Tab Delimited Data

Question

I have a data that looks like this:

1 1:-0.394668 2:-0.794872 3:-1 4:-0.871341 5:0.9365 6:0.75597 
1 1:-0.463641 2:-0.897436 3:-1 4:-0.871341 5:0.44378 6:0.121824 
1 1:-0.469432 2:-0.897436 3:-1 4:-0.871341 5:0.32668 6:0.302529 
-1 1:-0.241547 2:-0.538462 3:-1 4:-0.871341 5:0.9994 6:0.987166 
1 1:-0.757233 2:-0.948718 3:-1 4:-0.871341 5:-0.33904 6:0.915401 
1 1:-0.167147 2:-0.589744 3:-1 4:-0.871341 5:0.95078 6:0.991566 

The first column is class, and next 6 columns are features, I am trying to find all possible combination of features (2 features, 3 features, ... 5 features),

E.g.:

feat1 - feat2
feat1 - feat3
...
feat5 - feat6
...
feat1 - feat2 -feat3 -feat4 -feat 5
feat1 - feat2 -feat3 -feat4 -feat 6
..etc..

One of the file feat12.txt contains:

1 1:-0.394668 2:-0.794872
1 1:-0.463641 2:-0.897436
1 1:-0.469432 2:-0.897436
-1 1:-0.241547 2:-0.538462
1 1:-0.757233 2:-0.948718
1 1:-0.167147 2:-0.589744

Is there any existing implementation of that in Perl?