Strawberry Festival Held in Anhui Province

Question

Let's say I rename a augroup in my vimrc; what happens then? Do the autocmds inside that augroup get loaded twice? For example, let's say I rename the following augroup

augroup testgroup
    autocmd!
    autocmd BufWrite * :sleep 200m
    autocmd BufWrite * :echom "Foo"
    autocmd BufWrite * :echom "Bar"
augroup END

as

augroup TestGroup
    autocmd!
    autocmd BufWrite * :sleep 200m
    autocmd BufWrite * :echom "Foo"
    autocmd BufWrite * :echom "Bar"
augroup END

Answer 1

Your vimrc file is normally only loaded once per vim session. So if you change the file and rename the augroup, nothing happens in your running vim instance.

If you :source $MYVIMRC after you changed it you will end up with two versions of each of these autocommands. One in each group. To see which autocommands are defined you can execute

:au                "lists all autocommands (potentially very many)
:au BufWrite      " lists all autocommands for the BufWrite event
:au testgroup     " lists all autocommands in the group "testgroup"    
:au TestGroup     " lists all autocommands in the group "TestGroup"

In order to remove all autocommads of the "testgroup" in a running vim instance you can execute :au! testgroup.

You can start reading at :h :au.