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

my $txt = 'test';
my $foo = 'foo';
$txt =~ s/test/$foobar/;

print "$txt\n";

##</code><code>##

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

my $txt = 'test';
my $foo = 'foo';
my $fix = 'bar';

$txt =~ s/test/$foo$fix/;

print "$txt\n";

##</code><code>##

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

my $txt = '1,2';
$txt =~ s/(\d+)\.(\d+)/$10,$2/;

##</code><code>##

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

my $txt = '1,2';
my $fix = 0;
$txt =~ s/(\d+)\.(\d+)/$1$fix,$2/;

print "$txt\n";