Good idea. Well done. But you don't really need the extra last-number file. You can determine it on-the-fly. Hope the following code helps: The script will first look for sample_<number>.pl files, extract the biggest number, and start the next file with filename of sample_<last number + 1>.pl.

#!/usr/bin/perl -w
use strict;
use IO::Dir;

my $rootdir = ".";
my $lastno = GetLastNumber($rootdir) + 1;
my $newpl = "$rootdir/sample_${lastno}.pl"; # forgot to add .pl extens
+ion
                                            # thanks jweed.

system "vim $newpl && rm current_test && ln -s $newpl current_test";

sub GetLastNumber
{
    my $dir = shift;

    my $d = IO::Dir->new($dir)
          or die "Can not open directory $dir for read!";

    my $lastno = 0;
    while (defined(my $f = $d->read))
    {
        next if $f !~ /sample\_\d+\.pl/;
        my ($no) = $f =~ /sample_(\d+)\.pl/;
        $lastno = $no if $no > $lastno;
    }

    return $lastno;
}
[download]