Simplistically: 
#!/usr/bin/perl

use strict;
use warnings;
use Data::Dumper;

my $string = 'RAGGTS';

my @temp;
my @wanted;

if ( grep /R/, $string )
{
    my $orig = $string;
    $string =~ s/R/A/g;
    push @temp, $string;
    $string = $orig;
    $string =~ s/R/G/g;
    push @temp, $string;
}

for my $string_ (@temp)
{
    if ( grep /S/, $string_ )
    {
        my $orig = $string_;
        $string_ =~ s/S/C/g;
        push @wanted, $string_;
        $string_ = $orig;
        $string_ =~ s/S/G/g;
        push @wanted, $string_;
    }
}

print Dumper @itemb;

[download]

a recursive sub might make that a little cleaner though.

UPDATE

output is 
$VAR1 = 'AAGGTC';
$VAR2 = 'AAGGTG';
$VAR3 = 'GAGGTC';
$VAR4 = 'GAGGTG';

[download]
Ted
--
"That which we persist in doing becomes easier, not that the task itself has become easier, but that our ability to perform it has improved."
  --Ralph Waldo Emerson

In reply to Re: How to expand a string by tcf03
in thread How to expand a string by Anonymous Monk

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