How to comment in Vim?

Question

In VSCode I can comment my code with Ctrl+KCtrl+C and uncomment with Ctrl+KCtrl+U.

Is there any way to do the same in Vim?

Answer 1

Because "commenting out" is context-dependent, the behavior is left to plugins rather than the core Vim editor.

Many plugins reuse the sequence gc to comment.

• vim-commentary (authored by the prolific @tpope)
• comment.nvim (included in LunarVim)
• nerdcommenter (uses <Leader>cc)
• tcomment_vim (need and deserve love)
• vim-tag-comment (old but works very well for commenting tags)

Remark: With Neovim 0.10 (16th of May 2024) the commenting functionality is builtin in Neovim (bind to the gc command).

Remark: With Vim 9.1.0375 (26th of April 2024) Vim comes with a builtin commenting plugin (activated using the packadd comment command) [thanks to @Friedrich to pointing me this and to @MaximKim to make it possible]

Answer 2

The standard and advised approach is to use a plugin, like Vivian wrote.

If you feel like not using a plugin, you can do it in a few lines of code using autocmd like the snippet below. Select several lines in visual mode with V and press Ctrl-Slash or Shift-Ctrl-Slash to comment/uncomment.

The idea is simple. The buffer-local variable b:comment_symbol is defined corresponding to the file type (you can see with echo &ft). If you substitute b:comment_symbol for start-of-line, you comment a line. If you substitute nothing for b:comment_symbol at start-of-line, you uncomment a line.

(This is standard vim, sorry idk if it works in neovim or lunarvim)

augroup visual_commenting
    autocmd!
    autocmd FileType c,cpp,java,rust  let b:comment_symbol = '//'
    autocmd FileType vim              let b:comment_symbol = '"'
    autocmd FileType sh,vim,python    let b:comment_symbol = '#'
    autocmd FileType tex              let b:comment_symbol = '%'
    autocmd BufEnter * silent! vnoremap <silent> <C-_> :<C-u>keepp '<,'>s@^@\=b:comment_symbol<CR>
    autocmd BufEnter * silent! exec 'vnoremap <silent> <C-?> :<C-u>keepp ''<,''>s@^' . b:comment_symbol . '@<CR>'
augroup END

Answer 3

I feel the existing answers still miss something: you don't have this in Vim because you don't need it.

Turning a line of code into a comment is just a special case of line-wise text manipulation, which is something Vim is extremely powerful in.

The :substitute command to comment out a line is :s/^/#. This is the analogue to VSCode's Ctrl-KCtrl-C.

A workflow similar to what one would do in VSCode would be to use a text object to quickly span a visual selection and call :'<,'>s/^/# on it. This may look a bit clunky but you can always recall the command from history. Something like :s<Up> may suffice.

For example, to turn an entire paragraph into a comment using the # comment marker usually supported by scripting languages, you'd do:

vap:'<,'>s/^/#

See :help text-objects for all of them.

Uncommenting can be done likewise with :s/#\s*// to strip a comment marker followed by any number of white space. The improved version is :s/^\s*\zs#\s*// which will only trigger on a comment marker at the beginning of the line.

The alternative would be to use visual-block mode to select the column containing the comment markers and x them all away at once.

Another important property of Vim is that you can create mappings for recurring actions. If you frequently comment stuff, you'd create a pair of mappings (for normal and visual modes) in your vimrc or a filetype dependent .vim/after/ftplugin/<some filetype>.vim.

You can write all this yourself and stay in total control. I would guess every Vim veteran has, at some point in time, written a mapping related to commenting.

Some community members were nice enough to polish their solutions to work across all filetypes, toggle comments with a single command (really, why have two?) and work gracefully in corner cases. This is the origin of the plugins linked to in Vivian's answer.