#!/usr/bin/perl

my $string = "aaaaaaaaa";
$modifiers = "g";
$string =~ s/a/b/$modifiers;
print $string;

##</code><code>##

#!/usr/bin/perl

my $string = "aaaaabbbbaaaaaa";
$replace = "$1";
$string =~ s/a+(b+)a+/$replace/g;
print $string;