#! /usr/bin/perl

$str = "aaaaa\nbbbbb\nccccc\naaaaa\nddddd\neeeee\n" ;

@a = $str =~ /(aaaaa.*?)/gm ;

print "$a[0]\n" ;

##</code><code>##

aaaaa
bbbbb
ccccc

##</code><code>##

aaaaa
ddddd
eeeee