feat: add option reverse

bin/swapus

@@ -16,31 +16,24 @@
 # specific language governing permissions and limitations
 # under the License.
 
-class SwapUsage
-  def initialize
-    @processes = {}
+$LOAD_PATH << File.expand_path('../../lib', __FILE__)
+
+require 'optparse'
+require 'swapus'
+
+reverse = false
+
+OptionParser.new do |opts|
+  opts.banner = 'Usage: swapus [options]'
+
+  opts.on('-h', '--help', 'Show this message') do
+    puts opts
+    exit 0
   end
 
-  def get_processes
-    Dir['/proc/[0-9]*'].map do |pid_dir|
-      pid = File.basename(pid_dir).to_i
-      cmd = File.read("#{pid_dir}/cmdline").tr("\x00", ' ').strip
-      swap = File.read("#{pid_dir}/status")[/^VmSwap:\s+([0-9]+)\s+kB$/, 1].to_i
-
-      @processes[pid] = { cmd: cmd, swap: swap } if swap.positive?
-    end
+  opts.on('-r', '--reverse', 'Reverse the result order') do
+    reverse = true
   end
+end.parse!
 
-  def show
-    @processes.sort_by { |_, v| v[:swap] }.each do |pid, values|
-      puts "#{values[:swap]} kB [#{pid}] #{values[:cmd]}"
-    end
-  end
-
-  def run
-    get_processes
-    show
-  end
-end
-
-SwapUsage.new.run
+SwapUsage.new(reverse).run

lib/swapus.rb

@@ -0,0 +1,48 @@
+#!/usr/bin/env ruby
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+class SwapUsage
+  def initialize(reverse)
+    @processes = {}
+    @reverse   = reverse
+  end
+
+  def get_processes
+    Dir['/proc/[0-9]*'].map do |pid_dir|
+      pid  = File.basename(pid_dir).to_i
+      cmd  = File.read("#{pid_dir}/cmdline").tr("\x00", ' ').strip
+      swap = File.read("#{pid_dir}/status")[/^VmSwap:\s+([0-9]+)\s+kB$/, 1].to_i
+
+      @processes[pid] = { cmd: cmd, swap: swap } if swap.positive?
+    end
+  end
+
+  def show
+    @processes = @processes.sort_by { |_, v| v[:swap] }
+    @processes = @processes.reverse if @reverse
+
+    @processes.each do |pid, values|
+      puts "#{values[:swap]} kB [#{pid}] #{values[:cmd]}"
+    end
+  end
+
+  def run
+    get_processes
+    show
+  end
+end