How do I insert a comment into my vimrc fie?

Question

What is the syntax for inserting a comment or comments into the vimrc file?

Having trouble finding this on vim documentation online.

Answer 1

It's in a different help file (cmdline, help :comment):

                            *:quote* *:comment*
'"' at the start of a line causes the whole line to be ignored.  '"'
after a command causes the rest of the line to be ignored.  This can be used
to add comments.  Example:
    :set ai     "set 'autoindent' option
It is not possible to add a comment to a shell command ":!cmd" or to the
":map" command and a few others, because they see the '"' as part of their
argument.  This is mentioned where the command is explained.

The reason it's there is because vimrc is nothing but a sequence of command-line commands. Pretty much everything that applies to command-line mode works in vimrc.

Example of whole-line comment in vimrc:

" show tab line always
set showtabline=2

Answer 2

You can use " at the start of the line:

" A comment
set foo=bar

You can also do this after commands, to ignore the rest of the line:

set foo=bar  " A comment

However, you need to be careful when adding comments after commands. In mappings and :! commands it's downright impossible: inoremap a b " Map a to b won't work. The "comment" is seen as part of the command. The same applies when running shell commands with :!ls " a comment

In some other cases it may also cause unexpected behaviour. For example normal! p " A comment will have the space between the p and " inserted, and the comment part may also be evaluated if Vim guesses it as part of a command.

Another problem is adding comments in when running multiple commands, which is something I often do in autocommands. For example this won't work:

autocmd Filetype go
    \  echom "A message"  
    \  " echo a message
    \| echom "A second message"

As far as I know, there is no sane way to get this to work :-/

There are probably other caveats; I chose to not remember them and only use " at the start of a line :-)