Duplicate file finder

#!/usr/bin/perl

# Duplicate file finder,
# finds duplicate files based on SHA-1 hash.
#
# deletes all found duplicates.

# requires Digest::SHA1 to be installed from CPAN.

        use 5.010;
        use Digest::SHA1;

        my $subbit; if ($ARGV[0] eq "R") { $subbit = 1; } else { $subbit = 0; }
        my $sha1 = Digest::SHA1->new;
        my @flatSHA1;       # Array that holds all found
        my $hash;

    # start by getting all files, then convert to hash
        foreach my $filename ( &getFiles( $ENV{'PWD'}, $subbit ) )
        {

    # Get SHA-1 hash.
            open (FILE, "<", $filename);
            $sha1->addfile(FILE);

            $hash = $sha1->hexdigest;

            $sha1->reset;
            close FILE;

    #test for duplicates, if none found, add to SHA-1 list, else delete the file.
            unless (@flatSHA1 ~~ $hash)
            {
                push (@flatSHA1, $hash);
            } else {
                unlink $filename;
            }

        }

# returns an array of files.
# if element 1 is 1, recurse directories.
    sub getFiles
    {
        my $directory = $_[0];
        my @files;
        my @filelist;
        my @subdirs;

    # remove trailing slash if present
        $directory =~ s/\/$//;

    # iterate through directory
        chdir $directory;
        @filelist = glob "*";

        foreach my $filename (@filelist)
        {
    # if you are to recurse through subdirectories, recurse this subroutine to get all the files.
            if ( $_[1] == 1 )
            {
                if ( -d $filename )
                {
                    push ( @subdirs, $filename );
                }
            }
            push (@files, $directory . "/" .$filename) unless (-d $directory . "/" . $filename);
        }

    # if subdirectories were found, find files in them as well.
        foreach my $dirname (@subdirs)
        {
            push( @files, &getFiles($directory . "/" . $dirname, 1) );
        }

        return @files;
    }