When I read the comment help file, I found
It is not possible to add a comment to a shell command ":!cmd" or to the ":map" command and a few others (mainly commands that expect expressions) that see the '"' as part of their argument: ...
What is it mean?
I add the line ":!ls" to my vimrc file and nothing changes.
What it means you can't start a comment after the command; with ":!ls" the " is before the command and comments out the entire line, and that's okay, but something like this won't work:
:!ls / " List root directory
Because the " is interpreted as part of the shell command. It's the same with the :map commands; for example to create a map to add a quote at the end of the line we could do:
:nnoremap Q $a"<Esc>
But how will Vim know that " is what you intended to be part of the map or a comment? Vim solves this by just not interpreting comments for a few special commands.
