Rename mp4 files to file1.mp4, file2.mp4, file3.mp4, etc

AllFilesRenameAndNumber.pl

use 5.12.0;
use warnings;
use File::Spec;
use File::stat;

my $dirname = shift;
my $ext = 'mp4';
my $basename = "file";
my $count = 1;
my $new;

opendir (DIR, $dirname) or die "cannot open directory $dirname";
my @files = grep /.$ext/, readdir DIR;
closedir (DIR);

foreach (@files) {
	$new = "${basename}${count}.$ext";
	print "rename $_ ${basename}${count}.$ext\n";
	rename $_, $new or warn "rename: $_: $new: $!\n";
	$count++;
}