use strict;
use warnings;

my $existingFile;
my $filename;

print "provide filename: ";
$existingFile    = <STDIN>;
$filename        = "folder1";
chomp $existingFile;
chomp $filename;

if (-e $filename) {
  print "File Exists! Renaming with .[x]\n";
  my $counter++;
    rename "$existingFile", "$filename.[$counter]";
  } else {
    rename "$existingFile", "$filename";
}
exit;