#!/usr/bin/perl

=head1 block-devices

Display all block devices on system

  hdparm -t `block-devices`

=cut

use warnings;
use strict;
#use autodie;

open(my $proc, '<', '/proc/partitions');

my @header;
my $last_device;

my $name2col;
sub col {
	my ( $name, $line ) = @_;
	if ( ! $name2col ) {
		$name2col->{ $header[$_] } = $_ foreach 0 .. $#header;
	}
	$line =~ s/^\s+// || die "expected line to start with space: $_\n";
	my @c = split(/\s+/, $line, $#header + 1 );
	return $c[ $name2col->{ $name } ];
}

while(<$proc>) {
	chomp;
	if ( ! @header ) {
		@header = split(/\s+/, $_);
		next;
	}
	next unless $_;

	my $device = col 'name', $_;
	if ( $last_device && substr( $device, 0, length($last_device) ) eq $last_device ) {
		warn "# partition $device\n";
	} else {
		print '/dev/', $last_device = $device, $/;
	}
}