Vim Tips

To fulfill one of the goals laid out in Goals for 2021, I've taken to gather some tips for Vim.

It works well because I have to write a lot of C over ssh these days, so it's a perfect time for me to try and apply things I learn so I can actually remember whatever I read.

This page will probably be frequently updated in the forseeable future.

Edit: This page was updated frequently throughout 2021. No major updates are planned, although the article will see minor edits here and there.

General

:h(elp) is always your friend, i.e. :h gU
Vim commands only need the minimal number of letters to make the command unambiguous. i.e. :tab sp instead of :tab split
vim --version in command line or :version to see what options vim was compiled with.
:abbr Lunix Linux to replace "Lunix" with "Linux" whenever you mistype.
:make to make (of course, you can also do :!make)
:set makeprg=xxx to change the :make in vim.
Vim can do arithmetic: {count}<C-a> and {count}<C-x> to add and subtract. If you are not already not on a number, Vim will also move you to the next digit literal and apply the operation there. These features can come in handy if you want to use the . operator; i.e. to change a CSS property from 0px to -180px, you can simply just do 180<C-x>.... to repeat.
Setting paths: :set path+=./** will add all recursive directories, and then you can use :find to autocomplete file names.
Modifying root permission files: :w !sudo tee % > /dev/null
Spell check with :set spell. ]s and [s to navigate between errors. z= to suggest corrections to misspelled word. zg to add current word to spell file, and zw to remove it. <C-x>s in insert mode to activate auto-complete replacements for the word in question.
Running grep inside vim creates a quickfix list for you to jump to, which you can navigate with :cnext and :cprev.

Editing, Text Objects, Visual Mode

Use daW (delete a WORD) to delete a word plus its whitespace (as opposed to) diW (delete inside a WORD).
p for paragraph: i.e. dap: delete a paragraph.
Backspace-style deletions in insert mode: C-h one character, C-w one word, C-u start of line.
C-h and C-l to delete and add characters while under auto complete(C-n or C-p)
Delete directly:d\<PATTERN><CR> to delete from your cursor's position to the first occurence of PATTERN.
Replace mode with R: to quote Vim Documentation, each character you type replaces an existing character, starting with the character under the cursor.
o in Visual Mode to move to the other end of the selected text. This allows us to also extend our visual selection in the other direction.
gv to reselect the previous Visual Mode mode.
Vim text objects:i (inside) and a (around or all). t for XML tags. Example: cit to change the region inside XML tags.

Navigation

H, M, L respectively for top, middle, bottom of screen
Ctrl-U, Ctrl-D respectively for move half-page up, half-page down
Ctrl-B, Ctrl-F respectively for move half-page up, half-page down
Ctrl-I to reverse Ctrl-O (previous position)
% Jump to matching bracket for {}, [], ()
Display line movements: prefix with g. For example, gj and gk to move up and down display lines, and g0/g^ and g$ to move to the start/end of a line.
<C+]> to jump to a tag If you are not satisfied with your tag jump, try g<C+]>. You can also jump with :tag{keyword} or :tjump {keyword}.
^ takes you to the first non-whitespace letter of a line, while 0 takes you to the start no matter what.
gf will open the file under your cursor.
Ctrl+W gf will open the file under your cursor in a new tab.
Marks: m{a-zA-Z} to set a mark, and `m{mark} to jump to it.

Ex Commands (Command Line Mode)

:t (copy), :m (move), :d (delete)
Ranges: 2,5d deletes lines 2~5. Can also be used in conjunction with . (current line), $ (EOF), % (current file), \pattern, or even \pattern + 2 for the first occurrence of pattern plus two lines.
Using normal mode: start off by doing A; to add semicolon at the end of a line. Select rest of file by doing jVG, and then run :'<,'>normal. to apply the dot operator in the selected portions. Or even easier... do :%normal A;. Oh, it can even run macros... :%normal @q.to return to the previous buffer you left (the "alternating buffer")
:edit <Tab> to open other files in the directory
q: to open the command line history. You can modify your history here and run commands by hitting <CR>.
Combine features! Run current file in python: :!python %
:term and :shell opens up shells, although these tasks are generally better delegated to a separate tmux pane.
:read to read the results of the command line operation to the current buffer, i.e. :read ls

Buffers

:ls To the list of buffers active
:b _ to open buffers, substitute _ with buffer name or number
Any fragment of the buffer name can be used to open files, i.e. :b que for requests.py
This can be useful if you have files with different extension names, i.e. :b .h
num Ctrl+^ changes to buffer number.
Ctrl+^ or :b# to return to the previous buffer you left (the "alternating buffer")
:prev and :n(ext) to navigate between buffers forward and backward

Windows

:[v]sp(lit) {file} [Vertical] split of a buffer and open {file}. Also can be done with <C-w>s (horizontal split) and <C-w>v (vertical split).
<C-w><C-w> to cycle through windows
<C-w>c to close active window
<C-w>o to close all except active window
<C-w>+/- or :res(ize) +/- N to increase/decrease height, e.g. 20<C-w>+ or :res +20.
<C-w>>/< or :vert(ical) res(ize) +/- N to increase/decrease width, e.g. 30<C-w>< or :vert res +30.
<C-w>_ or :res(ize) to set height, e.g. 30<C-w>_ or :resize 30
<C-w>| or :vert(ical) res(ize) to set width, e.g. 30<C-w>| or :vert res 30
<C-w>_/| and :res(ize) and :vert(ical) res(ize) can be used without arguments to maximize/minimize in their respective axeses.

Tabs

Open vim tabbed by vim -p fst.foo snd.bar
Close tabs with Ctrl-w c.
gt for next tab, gT for previous tab, {i}gt for tab in position i
:tabs to show all tabs and their information
:tab sp(lit) opens the same window in a new tab
:tab ball expand each buffer to a tab of its own
Ctrl+W T to move current window to a new tab of its own.
:tabe {filename} Opens new tab with the file name.
:qa (or :wqa) : close all tabs and exit
:tabdo to apply same command to all tabs, i.e. :tabdo :q to exit all tabs
:tabc(lose) Close current tab page
:tabo(nly) to exit all tabs other than the current one. However, the tabs are still alive in the buffer list, i.e. you can see them with :ls, and revive them using :tab ball.
:tabm 0 Move current tab to first
:tabm Move current tab to last
:tabm {i} Move current tab to ith position
:tabfir(st) Go to first tab
:tabl(ast) Go to last tab

Matching, Searching, Substitution

* searches the current exact word selected.
g* does the same, but it will also find words that have the pattern as a substring.
Ctrl+r Ctrl+w will place the current word selected into the search buffer.
f, t, F, T allow you to jump to the first occurrence of the character to the right/left in the line. Additionally, using ; will allow you to repeat this search, or , for the other direction. You can also prefix them with a count, e.g. 3fy for the 3rd occurrence of "y" to the right.
A blank search // repeats the last search. Putting "e" at the end of a search, i.e. /<pattern>/e places your cursor to the end of the pattern. This also works for substitution.
q/ to bring up previous searches.
gn to work a match, e.g. gUgn to convert to upper case.
:%s applies the substitution command on every line and /g applies substitution for every occurrence in the line. In other words, % can be understood as for every row, and /g (misleadingly called global) can be understood as for every column.
\v to do very magic searches and \V to match verbatim in search/substitute. Very magic searches are similar to Perl-style regex (no weird escaping), and also allows exact match with \v<the>, for instance, if you want to search for "the" without "their", "they", etc.
In search/substitution, <C-r> for accessing registers, and \= for evaluating VimScript commands.
Advanced and rather convoluted method of swapping the word "dog" and "man" in a single pass:
/\v(:<man>|:<dog>)
:%s//\={"dog":"man","man":"dog"}[submatch(1)]/g
:g global and :v (inVerted global), e.g. :v/href/d deletes all lines that does not have "href" in it. or :g/TODO/t$ places all the TODO lines at the end of the file.

Registers

Access registers by " then register name, i.e. "r for the register r.
Example actions: "rp then "ry
Yanked/deleted lines stored in registers 0~9; yy→dd→"0p pastes the yanked content. Useful if you want to yank, delete, and then put the yanked text.
Black hole register "_, another option for deleting text and ignoring it.
In insert mode, <C-r> instead of ". This can be easier, as instead of playing around with p or P for put direction, it's very clear where you are going to put your text.
". has last inserted text.
"% has file path.
": has most recently used command (i.e. :w or :%s/foo/bar ).
/, ?, *, # have the last searched word, i.e. /foo→:%s/<Ctrl-r />/bar/gc is :%s/foo/bar/gc
"= expression register for dealing with results of expressions; i.e. in insert mode, <Ctrl-r />=2+2 or <Ctrl-r />=system('ls')
10@ to repeat the macro in register a 10 times.

Indentation

= indents. For instance, gg=G the entire file.
== indents the current line.
The autoindent setting copies the indentation from the previous line. Usually recommended.
The expandtab setting converts tabs to softtabstop number of spaces.

For hard tab-indentation, keep shiftwidth and tabstop to the same value:

                
                  set shiftwidth=4
                  set tabstop=4

If using space-based indentation (e.g. for Haskell), set expandtab and softtabstop:

                
                  set expandtab
                  set shiftwidth=4
                  set softtabstop=4

Plugins

I use Vundle for my plugin manager, although that is no longer necessary with Vim8+.

Below are a list of plugins I use. I don't use all of them together, but depending on my system (i.e. local machine v.s. ssh server), I use a mixture of them.

Wakatime: track your coding habits.
Ale: asynchronous syntax checker using Vim8+'s capabilities and Language Server Protocol (LSP)'s Easily my favorite plugin. Along with the next plugin, brings in the power of an IDE at the fraction of its cost.
YouCompleteMe: many autocomplete plugins exist: Vim's Native autocompletion, deoplete, VimCompletesMe, but I've found YouCompleteMe to be a powerful, easy-to-setup, still sufficiently fast autocompletion engine.
Syntastic: syntax checker that I use for linux kernel hacking, since it has out of box support for checkpatch. Also setting up vim to work with the linux kernel can be a pain.
Gutentags: automated tag generation.
Grammarous: nifty grammar checker if you write non-code (i.e. TeX) in vim.
VimTeX: TeX plugin for Vim, including features like auto compilation.
vim-commentary: gc to comment in virtually any language.
vim-tmux-navigator: nice integration with tmux.

VimScript

VimScript can be quite cursed at times, so it is necessary to avoid certain pitfalls. A large part of the tips here are taken from Learn VimScript the Hard Way by Steve Losh.

Scoping: Vim comes with many scopes, such as global(:g), buffer(:b), local to function (:l), etc. Check out :help internal-variables for more information.
Function naming: unscoped functions must start with a capital letter if they are unscoped! I.e. :function meow() will not work; it needs to be :function Meow() However, function g:meow() would work.
Unfortunately, the == operator may not do what you expect it to do... because it may depend on user setttings. If you have :set noignorecase on, "foo" == "FOO" will evaluate to TRUE! As a general rule, instead use ==# which is the "case-sensitive no matter what the user has set" comparison operator.