bug#46621: Copy line

[Helmut Eller]

On Mon, Feb 22 2021, Eli Zaretskii wrote:

> More importantly, I see no description of the situations where such a
> copy is needed, so it is hard to analyze reason about the necessity.

One example where copy-line would be useful is editing configuration
files.  E.g. /etc/ssh/sshd_config list many options with the default
value but as comments, like so:

  #SyslogFacility AUTH
  #LogLevel INFO
  ... other options ...
  
Now, if I want to change LogLevel to say DEBUG, I would copy the line,
keep the original, and edit the copied line.

Not hard to do in Emacs, but somehow the vi way of doing this feels more
efficient.

Helmut