How do I yank all matching lines into one buffer?

Question

How do you yank all matching lines into a buffer?

Given a file like:

match 1
skip
skip
match 2
match 3
skip

I want to be able issue a c

Answer 1

:g/^match/yank A

This runs the global command to yank any line that matches ^match and put it in register a. Because a is uppercase, instead of just setting the register to the value, it will append to it. Since the global command run the command against all matching lines, as a result you will get all lines appended to each other.

What this means is that you probably want to reset the register to an empty string before starting: :let @a="".

And naturally, you can use the same with any named register.

Answer 2

:help registers
:help quote_alpha

Specify a capital letter as the register name in order to append to it, like :yank A.

Answer 3

Oh I just realized after commenting above that it's easy to yank matching lines into a temporary buffer...

:r !grep "pattern" file.txt

The simplest solutions come once you've given up on finding them. :)