lvbar.rb is a `pvs` wrapper that shows allocation status of LVM logical volumes in bar chart

example.txt

$ sudo ruby lvbar.rb
/dev/sda0
  [aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa|bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb]
  a: vg_foo/lv_bar (54%)
  b: (unallocated) (46%)

/dev/sda1
  [aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa]
  a: vg_foo/lv_baz (100%)

/dev/sda2
  [aaaaaaaaaaaaaaa|bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb|c]
  a: vg_sys/lv_root (22%)
  b: vg_sys/lv_home (77%)
  c: vg_sys/lv_swap (2%)

lvbar.rb

#!/usr/bin/env ruby

Row = Struct.new(:pv_name, :pv_pe_count, :vg_name, :lv_name, :pvseg_start, :pvseg_size) do
  def name
    lv_name.empty? ? nil : "#{vg_name}/#{lv_name}"
  end
  
  def start_ratio
    Rational(pvseg_start, pv_pe_count)
  end
  
  def size_ratio
    Rational(pvseg_size, pv_pe_count)
  end
end

table = `pvs --noheadings --separator=: --options=#{PVS.members.join(',')}`.lines.map {|x| PVS.new *x.strip.split(/:/) }
 
pvs = table.group_by {|row| row.pv_name }
 
pvs.each do |pv_name, segments|
  puts pv_name
  puts "  [#{segments.each_with_index.map {|row, i| (i + 10).to_s(36) * ([(70 * row.size_ratio).to_i, 1].max) }.join('|')}]"
  segments.each_with_index do |row, i|
    puts "  #{(i + 10).to_s(36)}: #{row.name || '(unallocated)'} (#{(row.size_ratio * 100).round}%)"
  end
  puts
end

LVMの配置の具合を棒グラフでCUIで見たかったのでやっつけた。