This should work for you .. You were on the right track, but looks like you wanted a hash of arrays intead of a hash of a hash which is what your code was doing.

use strict;
use warnings;

my %h = ();
while(<DATA>){
 chomp;
 my ($comp,$cmd,$test) = split /-/, $_;
 push @{$h{$comp}->{$cmd}}, $test;
}
use Data::Dumper;
print Dumper \%h;

__DATA__
comp1-cmd1-test1
comp1-cmd1-test2
comp1-cmd2-test1
comp2-cmd1-test1
comp2-cmd1-test2
comp3-cmd1-test1
[download]