gistfile1.txt

ingy@thinkingy:~$ cat foo.pl 
use YAML::XS qw'LoadFile DumpFile';
use Hash::Merge 'merge';
use Template::Toolkit::Simple;
use IO::All;

my $stash = merge(
    LoadFile('b.yml'),
    LoadFile('a.yml'),
);
$stash = merge({title => 'Mr'}, $stash);

io('out')->print(
    tt->data($stash)->render("c.tt")
);
ingy@thinkingy:~$ cat a.yml 
first: Ingy
ingy@thinkingy:~$ cat b.yml 
last: döt Net
ingy@thinkingy:~$ cat c.tt 
Yo. I am [% title %] [% first %] [% last %].

ingy@thinkingy:~$ perl foo.pl; hexdump -C out 
00000000  59 6f 2e 20 49 20 61 6d  20 4d 72 20 49 6e 67 79  |Yo. I am Mr Ingy|
00000010  20 64 c3 b6 74 20 4e 65  74 2e 0a 0a              | d..t Net...|
0000001c