How to copy multiple lines in command line mode in vim?

Question

vim

I am using vscode and vim.
Do not judge strictly until I decide to completely switch to Linux, while I still work under Windows.
So, there are several lines

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Let's say I need to copy lines 3 to 8.
I call the command line mode through shift : and write
3,8yanka
, that is, copy lines 3 to 8 in register a, you can do without a.
But only this does not work, I get an error on the command line that this is not a vim command.
What is the reason?
Or am I not writing the command correctly, or is vim in vscode not working as it should?
Thanks in advance for your help.

Answer 1

I call the command line mode through shift : and write
3,8yanka
, that is, copy lines from 3 to 8 in register a, you can do without a.

I do the same in vim by adding a space between yank and a -- and it works. Conclusion: the problem is in vscode.