If you know the screen width, you can use formats.
If you don't, you could get the width from Term::Screen.
Given the screen width in $width, centering a single line is easy:

sub centerlines {
 my $width = shift;
 print map { ' ' x int($width/2 - length($_)/2) . $_ } @_;
}
centerlines($width, 'These', 'lines', 'are', 'centered');
[download]

2;0 juerd@ouranos:~$ perl -e'undef christmas'
Segmentation fault
2;139 juerd@ouranos:~$
[download]