#!/usr/bin/perl -w
use strict;
use warnings;
use FileHandle;

open my $fh, '>', '/tmp/output.txt' or die $!;

my $data = 'This is a test';
format LEFT  =
@<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
$data
.
format RIGHT = 
@>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
$data
.

format_name $fh "LEFT";
write ($fh) or die $!;
format_name $fh "RIGHT";
write ($fh) or die $!;

close ($fh) or die $!;
exit;