Vidul Nikolaev Petrov

use strict;
use Getopt::Std;
use File::Basename;
 
getopts('scf:p:');
 
our($opt_s, $opt_c, $opt_f, $opt_p);
 
my $file = $opt_f;
my $size = $opt_p || 1;
my $len  = 1024;
my $c = 1;
my ($buf, $counter);
 
-f $file or usage();
 
if($opt_s){
    $size = 1024 * $size;
 
    open IN, "< $file" or die "cannot open_r $file $!";
    open OUT, "> $file.$c"  or die "cannot open_w $file $!";
    binmode IN;
    binmode OUT;
 
    while(read(IN, $buf, $len)){
        $counter++;
        if($counter > $size){
            $counter = 0;
            $c++;
            close OUT;
            open OUT, "> $file.$c"  or die "cannot open_w $file $!";
            binmode OUT;
        }
        print OUT $buf
    }
} elsif($opt_c) {
    my @files = grep { -f and /^$file\.\d+$/ } glob '*';
    my $newfile = "splitter_$file";
    open OUT, ">> $newfile" or die "cannot open_w $file $!";
    binmode OUT;
    map { $_ =~ s/^$file\.// } @files;
    for(sort {$a< =>$b} @files ){
        open IN, "$file.$_" or die "cannot open_r $file $!";
        binmode IN;
        print OUT $_ while <in>;
        close IN;
    }
} else {
    usage()
}
 
sub usage{
    my $pro = basename($0);
    print < <SQ;
 
$pro (-s|-c) -p piece size -f filename
 
    -s    split a file into pieces
    -c    collect a file from pieces
    -p     chunk size (defaults to 1MB)
    -f     file to be processed
SQ
    exit 1
}