args.rb

task :goodbye, [:name, :alias] do |t, args|
  puts "Goodbye, #{args.name} the #{args.alias}!"
end

default.rb

task :default => :hello

desc.rb

task :default => :hello

desc '挨拶をします'
task :hello do
  puts "Hello!"
end

desc '名前とニックネームを引数にとり、別れの挨拶をします'
task :goodbye, [:name, :nickname] do |t, args|
  puts "Goodbye, #{args.name} the #{args.nickname}!"
end


namespace :math do
  desc '二乗を計算します'
  task :square, [:n] do |t, args|
    n = args.n.to_i
    puts n * n
  end
  desc '三乗を計算します'
  task :cube, [:n] do |t, args|
    n = args.n.to_i
    puts n * n * n
  end
end

dir.rb

directory 'hoge/fuga/piyo'

doargs.sh

$ rake "goodbye[Rake, greeter]"
Goodbye, Rake the greeter!

dodefault.sh

$ rake
Hello!

dodesc.sh

$ rake -T
rake goodbye[name,nickname]  # 名前とニックネームを引数にとり、別れの挨拶をします
rake hello                   # 挨拶をします
rake math:cube[n]            # 三乗を計算します
rake math:square[n]          # 二乗を計算します

dodir.sh

$ rake hoge/fuga/piyo
mkdir -p hoge/fuga/piyo

dofile.sh

$ ls
Rakefile

$ rake hoge.txt
writing hoge.txt

$ ls
Rakefile hoge.txt

$ cat hoge.txt
texttext

$ rake hoge.txt # 何も起こらない

dohello.sh

$ rake hello
Hello!

donamespace.sh

$ rake "math:square[2]"
4

$ rake "math:cube[2]"
8

file.rb

file 'hoge.txt' do
  puts 'writing hoge.txt'
  open('./hoge.txt', 'w'){|f| f.write 'texttext' }
end

hello.rb

task :hello do
  puts 'Hello!'
end

install.sh

$ gem install rake
rake's executable "rake" conflicts with /Users/hash/.rbenv/versions/2.0.0-p353/bin/rake
Overwrite the executable? [yN]  y
Successfully installed rake-10.1.1
1 gem installed

$ rake --version
rake, version 10.1.1

namespace.rb

namespace :math do
  task :square, [:n] do |t, args|
    n = args.n.to_i
    puts n * n
  end
  task :cube, [:n] do |t, args|
    n = args.n.to_i
    puts n * n * n
  end
end

norakefile.sh

$ rake
rake aborted!
No Rakefile found (looking for: rakefile, Rakefile, rakefile.rb, Rakefile.rb)

(See full trace by running task with --trace)

ps_fork.sh

$ ruby fork.rb
$ ps aux | grep "[r]uby" # (別ターミナルで)
hash            45929   0.0  0.0  2457176    456 s001  S     8:33AM   0:00.00 ruby fork.rb
hash            45928   0.0  0.0  2457176    456 s001  S     8:33AM   0:00.00 ruby fork.rb
hash            45927   0.0  0.0  2457176    456 s001  S     8:33AM   0:00.00 ruby fork.rb
hash            45926   0.0  0.0  2457176    456 s001  S     8:33AM   0:00.00 ruby fork.rb
hash            45925   0.0  0.0  2457176    456 s001  S     8:33AM   0:00.00 ruby fork.rb
hash            45924   0.0  0.0  2457176    456 s001  S     8:33AM   0:00.00 ruby fork.rb
hash            45923   0.0  0.0  2457176    456 s001  S     8:33AM   0:00.00 ruby fork.rb
hash            45922   0.0  0.0  2457176    456 s001  S     8:33AM   0:00.00 ruby fork.rb
hash            45921   0.0  0.0  2457176    456 s001  S     8:33AM   0:00.00 ruby fork.rb
hash            45920   0.0  0.0  2457176    456 s001  S     8:33AM   0:00.00 ruby fork.rb