[ERROR] /usr/local/lib/ruby/1.9.1/webrick/utils.rb:73:in `initialize': Address already in use - bind(2) (Errno::EADDRINUSE)

"rails s" コマンドを実行すると以下のエラーが出た.
どうやら、既に起動してるみたい...

=> Booting WEBrick
=> Rails 3.2.1 application starting in development on http://0.0.0.0:3000
=> Call with -d to detach
=> Ctrl-C to shutdown server
[2012-03-08 10:25:27] INFO  WEBrick 1.3.1
[2012-03-08 10:25:27] INFO  ruby 1.9.2 (2010-12-25) [i686-linux]
[2012-03-08 10:25:27] WARN  TCPServer Error: Address already in use - bind(2)
Exiting
/usr/local/lib/ruby/1.9.1/webrick/utils.rb:73:in `initialize': Address already in use - bind(2) (Errno::EADDRINUSE)
        from /usr/local/lib/ruby/1.9.1/webrick/utils.rb:73:in `new'
        from /usr/local/lib/ruby/1.9.1/webrick/utils.rb:73:in `block in create_listeners'
        from /usr/local/lib/ruby/1.9.1/webrick/utils.rb:70:in `each'
        from /usr/local/lib/ruby/1.9.1/webrick/utils.rb:70:in `create_listeners'
        from /usr/local/lib/ruby/1.9.1/webrick/server.rb:74:in `listen'
        from /usr/local/lib/ruby/1.9.1/webrick/server.rb:62:in `initialize'
        from /usr/local/lib/ruby/1.9.1/webrick/httpserver.rb:24:in `initialize'
        from /usr/local/lib/ruby/gems/1.9.1/gems/rack-1.4.1/lib/rack/handler/webrick.rb:10:in `new'
        from /usr/local/lib/ruby/gems/1.9.1/gems/rack-1.4.1/lib/rack/handler/webrick.rb:10:in `run'
        from /usr/local/lib/ruby/gems/1.9.1/gems/rack-1.4.1/lib/rack/server.rb:265:in `start'
        from /usr/local/lib/ruby/gems/1.9.1/gems/railties-3.2.1/lib/rails/commands/server.rb:70:in `start'
        from /usr/local/lib/ruby/gems/1.9.1/gems/railties-3.2.1/lib/rails/commands.rb:55:in `block in '
        from /usr/local/lib/ruby/gems/1.9.1/gems/railties-3.2.1/lib/rails/commands.rb:50:in `tap'
        from /usr/local/lib/ruby/gems/1.9.1/gems/railties-3.2.1/lib/rails/commands.rb:50:in `'
        from script/rails:6:in `require'
        from script/rails:6:in `
'

対処

既に起動してるプロセスを切ればいいので以下のコマンドで確認

# netstat -anp

Proto...tcp, Program name...ruby の行を発見！ PID より "kill "する.

参考サイト

CentOS5 不要なサービスの停止 - itochif.com