Vim error E492: Not an editor command: dd

I started learning vim today and installed it using

sudo apt-get install vim

Now, when I try to do something like :5dd it gives me the not an editor command error. I'm not sure why this is.

Am I doing anything开发者_高级运维 wrong? I looked at tutorials and everywhere I look I see that 5dd is a valid command.

:5dd is not the same as just 5dd. You use 5dd in normal mode to delete 5 lines, you can use :5delete or just :5d to do the same thing as a command.