Besides the push solution, you can also print to a filehandle that has been opened to an in-memory variable:

my $output;                                         
open my $fd, '>', \$output or die "open: $!";
## print to the $output scalar
print $fd "hello\n";
print $fd "world\n";
close $fd;
## use results
print $output;
__END__
hello
world
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