Learn-Vim/ch03_searching_files.md

Ch03. Searching Files

The goal of this chapter is to give you an introduction on how to search quickly in Vim. Being able to search quickly is a great way to jump-start your Vim productivity. When I figured out how to search files quickly, I made the switch to use Vim full-time.

This chapter is divided into two parts: how to search without plugins and how to search with fzf.vim plugin. Let's get started!

Opening and Editing Files

To open a file in Vim, you can use :edit.

:edit file.txt

If file.txt exists, it opens the file.txt buffer. If file.txt doesn't exist, it creates a new buffer for file.txt.

Autocomplete with <Tab> works with :edit. For example, if your file is inside a Rails app controller users controller directory ./app/controllers/users_controllers.rb, you can use <Tab> to expand the terms quickly:

:edit a<Tab>c<Tab>u<Tab>

:edit accepts wildcards arguments. * matches any file in the current directory. If you are only looking for files with .yml extension in the current directory:

:edit *.yml<Tab>

Vim will give you a list of all .yml files in the current directory to choose from.

You can use ** to search recursively. If you want to look for all *.md files in your project, but you are not sure in which directories, you can do this:

:edit **/*.md<Tab>

:edit can be used to run netrw, Vim's built-in file explorer. To do that, give :edit a directory argument instead of file:

:edit .
:edit test/unit/

Searching Files With Find

You can find files with :find. For example:

:find package.json
:find app/controllers/users_controller.rb

Autocomplete also works with :find:

:find p<Tab>                " to find package.json
:find a<Tab>c<Tab>u<Tab>    " to find app/controllers/users_controller.rb

You may notice that :find looks like :edit. What's the difference?

Find and Path

The difference is that :find finds file in path, :edit doesn't. Let's learn a little bit about path. Once you learn how to modify your paths, :find can become a powerful searching tool. To check what your paths are, do:

:set path?

By default, yours probably look like this:

path=.,/usr/include,,

• . means to search in the directory of the currently opened file.
• , means to search in the current directory.
• /usr/include is the typical directory for C libraries header files.

The first two are important in our context and the third one can be ignored for now. The takeaway here is that you can modify your own paths, where Vim will look for files. Let's assume this is your project structure:

app/
  assets/
  controllers/
    application_controller.rb
    comments_controller.rb
    users_controller.rb
    ...

If you want to go to users_controller.rb from the root directory, you have to go through several directories (and pressing a considerable amount of tabs). Often when working with a framework, you spend 90% of your time in a particular directory. In this situation, you only care about going to the controllers/ directory with the least amount of keystrokes. The path setting can shorten that journey.

You need to add the app/controllers/ to the current path. Here is how you can do it:

:set path+=app/controllers/

Now that your path is updated, when you type :find u<Tab>, Vim will now search inside app/controllers/ directory for files starting with "u".

If you have a nested controllers/ directory, like app/controllers/account/users_controller.rb, Vim won't find users_controllers. Instead, you need to add :set path+=app/controllers/** in order for autocompletion will find users_controller.rb. This is great! Now you can find the users controller with 1 press of tab instead of 3.

You might be thinking to add the entire project directories so when you press tab, Vim will search everywhere for that file, like this:

:set path+=$PWD/**

$PWD is the current working directory. If you try to add your entire project to path hoping to make all files reachable upon a tab press, although this may work for a small project, doing this will slow down your search significantly if you have a large number of files in your project. I recommend adding only the path of your most visited files / directories.

You can add the set path+={your-path-here} in your vimrc. Updating path takes only a few seconds and doing so can save you a lot of time.

Searching in Files With Grep

If you need to find in files (find phrases in files), you can use grep. Vim has two ways of doing that:

• Internal grep (:vim. Yes, it is spelled :vim. It is short for :vimgrep).
• External grep (:grep).

Let's go through internal grep first. :vim has the following syntax:

:vim /pattern/ file

• /pattern/ is a regex pattern of your search term.
• file is the file argument. You can pass multiple arguments. Vim will search for the pattern inside the file argument. Similar to :find, you can pass it * and ** wildcards.

For example, to look for all occurrences of "breakfast" string inside all ruby files (.rb) inside app/controllers/ directory:

:vim /breakfast/ app/controllers/**/*.rb

After running that, you will be redirected to the first result. Vim's vim search command uses quickfix operation. To see all search results, run :copen. This opens a quickfix window. Here are some useful quickfix commands to get you productive immediately:

:copen        Open the quickfix window
:cclose       Close the quickfix window
:cnext        Go to the next error
:cprevious    Go to the previous error
:colder       Go to the older error list
:cnewer       Go to the newer error list

To learn more about quickfix, check out :h quickfix.

You may notice that running internal grep (:vim) can get slow if you have a large number of matches. This is because Vim loads each matching file into memory, as if it were being edited. If Vim finds a large number of files matching your search, it will load them all and therefore consume a large amount of memory.

Let's talk about external grep. By default, it uses grep terminal command. To search for "lunch" inside a ruby file inside app/controllers/ directory, you can do this:

:grep -R "lunch" app/controllers/

Note that instead of using /pattern/, it follows the terminal grep syntax "pattern". It also displays all matches using quickfix.

Vim defines the grepprg variable to determine which external program to run when running the :grep Vim command so that you don't have to close Vim and invoke the terminal grep command. Later, I will show you how to change the default program invoked when using the :grep Vim command.

Browsing Files With Netrw

netrw is Vim's built-in file explorer. It is useful to see a project's hierarchy. To run netrw, you need these two settings in your .vimrc:

set nocp
filetype plugin on

Since netrw is a vast topic, I will only cover the basic usage, but it should be enough to get you started. You can start netrw when you launch Vim by passing it a directory as a parameter instead of a file. For example:

vim .
vim src/client/
vim app/controllers/

To launch netrw from inside Vim, you can use the :edit command and pass it a directory parameter instead of a filename:

:edit .
:edit src/client/
:edit app/controllers/

There are other ways to launch netrw window without passing a directory:

:Explore     Starts netrw on current file
:Sexplore    No kidding. Starts netrw on split top half of the screen
:Vexplore    Starts netrw on split left half of the screen

You can navigate netrw with Vim motions (motions will be covered in depth in a later chapter). If you need to create, delete, or rename a file or directory, here is a list of useful netrw commands:

%    Create a new file
d    Create a new directory
R    Rename a file or directory
D    Delete a file or directory

:h netrw is very comprehensive. Check it out if you have time.

If you find netrw too bland and need more flavor, vim-vinegar is a good plugin to improve netrw. If you're looking for a different file explorer, NERDTree is a good alternative. Check them out!

Fzf

Now that you've learned how to search files in Vim with built-in tools, let's learn how to do it with plugins.

One thing that modern text editors get right and that Vim didn't is how easy it is to find files, especially via fuzzy search. In this second half of the chapter, I will show you how to use fzf.vim to make searching in Vim easy and powerful.

Setup

First, make sure you have fzf and ripgrep downloaded. Follow the instruction on their github repo. The commands fzf and rg should now be available after successful installs.

Ripgrep is a search tool much like grep (hence the name). It is generally faster than grep and has many useful features. Fzf is a general-purpose command-line fuzzy finder. You can use it with any commands, including ripgrep. Together, they make a powerful search tool combination.

Fzf does not use ripgrep by default, so we need to tell fzf to use ripgrep by defining a FZF_DEFAULT_COMMAND variable. In my .zshrc (.bashrc if you use bash), I have these:

if type rg &> /dev/null; then
  export FZF_DEFAULT_COMMAND='rg --files'
  export FZF_DEFAULT_OPTS='-m'
fi

Pay attention to -m in FZF_DEFAULT_OPTS. This option allows us to make multiple selections with <Tab> or <Shift-Tab>. You don't need this line to make fzf work with Vim, but I think it is a useful option to have. It will come in handy when you want to perform search and replace in multiple files which I'll cover in just a little. The fzf command accepts many more options, but I won't cover them here. To learn more, check out fzf's repo or man fzf. At minimum you should have export FZF_DEFAULT_COMMAND='rg'.

After installing fzf and ripgrep, let's set up the fzf plugin. I am using vim-plug plugin manager in this example, but you can use any plugin managers.

Add these inside your .vimrc plugins. You need to use fzf.vim plugin (created by the same fzf author).

Plug 'junegunn/fzf.vim'
Plug 'junegunn/fzf', { 'do': { -> fzf#install() } }

After adding these lines, you will need to open vim and run :PlugInstall. It will install all plugins that are defined in your vimrc file and are not installed. In our case, it will install fzf.vim and fzf.

For more info about this plugin, you can check out fzf.vim repo.

Fzf Syntax

To use fzf efficiently, you should learn some basic fzf syntax. Fortunately, the list is short:

• ^ is a prefix exact match. To search for a phrase starting with "welcome": ^welcome.
• $ is a suffix exact match. To search for a phrase ending with "my friends": friends$.
• ' is an exact match. To search for the phrase "welcome my friends": 'welcome my friends.
• | is an "or" match. To search for either "friends" or "foes": friends | foes.
• ! is an inverse match. To search for phrase containing "welcome" and not "friends": welcome !friends

You can mix and match these options. For example, ^hello | ^welcome friends$ will search for the phrase starting with either "welcome" or "hello" and ending with "friends".

Finding Files

To search for files inside Vim using fzf.vim plugin, you can use the :Files method. Run :Files from Vim and you will be prompted with fzf search prompt.

Since you will be using this command frequently, it is good to have this mapped to a keyboard shortcut. I map mine to Ctrl-f. In my vimrc, I have this:

nnoremap <silent> <C-f> :Files<CR>

Finding in Files

To search inside files, you can use the :Rg command.

Again, since you will probably use this frequently, let's map it to a keyboard shortcut. I map mine to <Leader>f.

nnoremap <silent> <Leader>f :Rg<CR>

Other Searches

Fzf.vim provides many other search commands. I won't go through each one of them here, but you can check them out here.

Here's what my fzf maps look like:

nnoremap <silent> <Leader>b :Buffers<CR>
nnoremap <silent> <C-f> :Files<CR>
nnoremap <silent> <Leader>f :Rg<CR>
nnoremap <silent> <Leader>/ :BLines<CR>
nnoremap <silent> <Leader>' :Marks<CR>
nnoremap <silent> <Leader>g :Commits<CR>
nnoremap <silent> <Leader>H :Helptags<CR>
nnoremap <silent> <Leader>hh :History<CR>
nnoremap <silent> <Leader>h: :History:<CR>
nnoremap <silent> <Leader>h/ :History/<CR>

Replacing Grep With Rg

As mentioned earlier, Vim has two ways to search in files: :vim and :grep. :grep uses external search tool that you can reassign using the grepprg keyword. I will show you how to configure Vim to use ripgrep instead of terminal grep when running the :grep command.

Now let's setup grepprg so that the :grep Vim command uses ripgrep. Add this in your vimrc:

set grepprg=rg\ --vimgrep\ --smart-case\ --follow

Feel free to modify some of the options above! For more information on what the options above mean, check out man rg.

After you updated grepprg, now when you run :grep, it runs rg --vimgrep --smart-case --follow instead of grep. If you want to search for "donut" using ripgrep, you can now run a more succinct command :grep "donut" instead of :grep "donut" . -R

Just like the old :grep, this new :grep also uses quickfix to display results.

You might wonder, "Well, this is nice but I never used :grep in Vim, plus can't I just use :Rg to find phrases in files? When will I ever need to use :grep?

That is a very good question. You may need to use :grep in Vim to do search and replace in multiple files, which I will cover next.

Search and Replace in Multiple Files

Modern text editors like VSCode makes it very easy to search and replace a string across multiple files. In this section, I will show you two different methods to easily do that in Vim.

The first method is to replace all matching phrases in your project. You will need to use :grep. If you want to replace all instances of "pizza" with "donut", here's what you do:

:grep "pizza"
:cfdo %s/pizza/donut/g | update

Let's break down the commands:

1. :grep pizza uses ripgrep to search for all instances of "pizza" (by the way, this would still work even if you didn't reassign grepprg to use ripgrep. You would have to do :grep "pizza" . -R instead of :grep "pizza").
2. :cfdo executes any command you pass to all files in your quickfix list. In this case, your command is the substitution command %s/pizza/donut/g. The pipe (|) is a chain operator. The update command saves each file after substitution. I will cover the substitute command in more depth in a later chapter.

The second method is to search and replace in selected files. With this method, you can manually choose which files you want to perform select-and-replace on. Here is what you do:

1. Clear your buffers first. It is imperative that your buffer list contains only the files you want to apply the replace on. You can either restart Vim or run :%bd | e# command (%bd deletes all the buffers and e# opens the file you were just on).
2. Run :Files.
3. Select all files you want to perform search-and-replace on. To select multiple files, use <Tab> / <Shift-Tab>. This is only possible if you have the multiple flag (-m) in FZF_DEFAULT_OPTS.
4. Run :bufdo %s/pizza/donut/g | update. The command :bufdo %s/pizza/donut/g | update looks similar to the earlier :cfdo %s/pizza/donut/g | update command. The difference is instead of substituting all quickfix entries (:cfdo), you are substituting all buffer entries (:bufdo).

Learn Search the Smart Way

Searching is the bread-and-butter of text editing. Learning how to search well in Vim will improve your text editing workflow significantly.

Fzf.vim is a game-changer. I can't imagine using Vim without it. I think it is very important to have a good search tool when starting Vim. I've seen people struggling to transition to Vim because it seems to be missing critical features modern text editors have, like an easy and powerful search feature. I hope this chapter will help you to make the transition to Vim easier.

You also just saw Vim's extensibility in action - the ability to extend search functionality with a plugin and an external program. In the future, keep in mind of what other features you wish to extend Vim with. Chances are, it's already in Vim, someone has created a plugin or there is a program for it already. Next, you'll learn about a very important topic in Vim: Vim grammar.