Filter stdin to stdout, using line-ranges described by binary strings.

linesplit.pl

#!/usr/bin/env perl
# Takes M parameters on the command line, binary strings of N digits.
# Filters stdin to stdout, printing only lines whose indices fall inside (or
# outside, if -invert is specified) the independent ranges specified by the
# binary string, where "" means "everything", "0" means "the first half", "01"
# means "the first quarter", "111" means "the last eighth" and so on.

use strict;

my @lines = <STDIN>;
my $count = @lines;
for my $spec (@ARGV) {
    my $val   = oct "0b$spec";
    my $width = 1 << (length $spec);
    my $start = $val / $width;
    my $end   = $start + (1 / $width);

    my ($a, $b) = ($start * $count, $end * $count - 1);
    if ($::invert) {
        @lines[$a .. $b] = undef;
    } else {
        print @lines[$a .. $b];
    }
}

print grep defined, @lines if $::invert;