It's possible to do that, but it's not really the easiest way.

Consider using a hash instead:

my %files = (
     'file1' => 'tom',
     'file2' => 'bob',
     'file3' => 'joe',
);

$files{'file2'} = 'sam';
[download]

Alternately, just store your filenames in the array (if order is important), like:

my @names = ('tom','bob','joe');
$names[1] = 'sam';
[download]

Adding the additional step of the array of variable names is usally the wrong path to go down.