ABCTEST_062506.DAT
XYZTEST_062506.DAT
ABCTEST_062406.DAT
XYZTEST_062506.DAT
ABCTEST_062406.DAT
XYZTEST_062506.DAT
ABCTEST_062406.DAT
XYZTEST_062506.DAT

##</code><code>##

sub scanDir()
{
        $check ="ABCD" # this value will come from an array 
	$base_dir = $_[0];
	opendir(DIR, $base_dir) || die "Error: could not open input directory $base_dir";
        @current_dir = readdir(DIR);
	chomp(@current_dir);
	foreach $current_dirs (@current_dir) 
	{
		$file_name = $current_dirs;
                $var = substr($file_name, 0, 3);
                $newvar = substr($file_name,3);
                if($var eq $check){
                   $newFileName = $check . $newvar;
                }
	}
 closedir(DIR);
}