script for crc checking/tagging files, windows or linux

CRC.pl

#!C:\perl\perl\bin

# sudo apt-get install libmodern-perl-perl libstring-crc32-perl

use Modern::Perl;
use String::CRC32;
my $sil = 0;
my $debugmode = 0;
my $start = time;
my @files;
if (@ARGV){
	if ($ARGV[0] =~ /^-q/){ 
		shift @ARGV; 
		$sil = 1; 
	}
	@files = @ARGV;
} else { #if you invoke without any arguments, it'll do the whole directory
	@files = glob "*.*";
}
$sil++ if scalar @files > 25;

for my $this (@files){
	unless (-e $this && -w $this){
		say $this." doesn't exist or isn't writable";
		next;
	}
	my ($name,$ext) = $this =~ /^(.+?)\.(\w{2,4})$/;
	say $name if $debugmode;
	
	open my $file, $this || die $!;
	binmode($file);
	
	my $hash = crc32(*$file);
		
	say $hash if $debugmode;
	close $file;
	
	$hash =~ s/^(.+)$/uc sprintf "%08x", $1/eg; #why did I do this in a regex?
	say $hash if $debugmode;
	
	if ($this =~ /\[([0-9A-F]{8})\]/){ #if the filename has a conventional "[A67F3C23]"-style crc tag, check it
		say $1 if $debugmode;
		my $oldhash = $1;
		#all this sprintf stuff right-aligns the actual CRC and OK/NOT OK message
		printf "%-70s OK\n", (sprintf "%s %".(70-(length $this))."s", ($this, "($hash)")) if uc $oldhash eq $hash;
		printf "%-70s NOT OK\n", (sprintf "%s %".(70-(length $this))."s", ($this, "($hash)")) if uc $oldhash ne $hash;
		say 'next after check' if $debugmode;
		next;
	} else { #and if it was untagged, tag it with one
		say $this.' => '.$hash;
		
		$name .= ' ['.$hash.'].'.$ext;
		$name =~ s/\] +\[/][/g;
		rename ($this, $name) || die $!;
		say $name if $debugmode;
		say 'next after rename' if $debugmode;
		next;
	}
	say 'next' if $debugmode;
	next;
}
if (! $sil){
	say 'took '.(time - $start).' seconds ('.(scalar @files).' files)';
	$^O eq 'MSWin32' 
		? system 'pause' 
		#I say 'any', but it might have to be enter? If so, listening to stdin makes more sense
		: system 'read -p "Press any key to continue."'; 
	exit;
}