如何在Perl中每个非空行的开头和结尾添加字符？

#!/usr/bin/perl
use strict;
use warnings;

my $input = "This is a sample text file.
This is the second line.

This is the fourth line.
";

# 使用正则表达式匹配非空行，并在开头和结尾添加字符
$input =~ s/^(.+)$/start_$1_end/gm;

print $input;

start_This is a sample text file._end
start_This is the second line._end

start_This is the fourth line._end