我的代码如下：

class Song

    def initialize(name)

        @name = name

    end

    def tell

        puts @name

    end

end

class ZhouSong < Song

    def initialize(name,artist)

        super(name)

        @artist = artist

    end

    def tell

        super

        puts @artist

    end

    def name=(newName)

        @name = newName

    end

    

    attr_writer :artist

end

s = Song.new("song")

s.tell

zs = ZhouSong.new("zhousong","zhoujielun")

zs.tell

zs.name = "name : new zhou song"

zs.tell

zs.artist = "artist : zhoujielun "

zs.tell

我希望删除所有的空行，可以用sed来实现

文件名是a.rb

more a.rb | sed "/^\s*$/d"

结果如下：

class Song

        def initialize(name)

                @name = name

        end

        def tell

                puts @name

        end

end

class ZhouSong < Song

        def initialize(name,artist)

                super(name)

                @artist = artist

        end

        def tell

                super

                puts @artist

        end

        def name=(newName)

                @name = newName

        end

        attr_writer :artist

end

s = Song.new("song")

s.tell

zs = ZhouSong.new("zhousong","zhoujielun")

zs.tell

zs.name = "name : new zhou song"

zs.tell

zs.artist = "artist : zhoujielun "

zs.tell

如果您想直接修改文件，那么可以用

sed -i "/^\s*$/d" a.rb