How can I delete multiple lines in vi?

Question

I have tried to follow the following:

How to delete selected text in VI editor

but

5dd

gives

E492: Not a

Answer 1

Sounds like you're entering the commands in command mode (aka. "Ex mode"). In that context :5d would remove line number 5, nothing else. For 5dd to work as intended -- that is, remove five consequent lines starting at the cursor -- enter it in normal mode and don't prefix the commands with :.