Search and Replace

Neovim's search-and-replace system is one of the most powerful in any text editor. It uses regular expressions, supports range-limited substitution, can operate across multiple files, and provides real-time preview with inccommand.

Core Idea

The substitute command syntax is: :[range]s/pattern/replacement/[flags] Once you know the parts, you can build any substitution precisely.

Basic Searching

/pattern          → Search forward
?pattern          → Search backward
n                 → Next match
N                 → Previous match
*                 → Search word under cursor (forward)
#                 → Search word under cursor (backward)
:noh              → Clear search highlight

Enable Live Search Highlight

~/.config/nvim/lua/config/options.lua
vim.opt.incsearch = true     -- show matches as you type
vim.opt.hlsearch = true      -- highlight all matches
vim.opt.ignorecase = true    -- case insensitive by default
vim.opt.smartcase = true     -- case sensitive if uppercase in pattern

The Substitute Command

:[range]s/{pattern}/{replacement}/[flags]

Ranges

Range	Meaning
(none)	Current line only
`%`	Entire file
`1,10`	Lines 1 to 10
`'<,'>`	Visual selection (auto-inserted)
`.,+5`	Current line + 5 lines
`.,/end/`	Current line to line containing "end"

Flags

Flag	Meaning
`g`	Global — replace all on each line
`i`	Case insensitive
`I`	Case sensitive (override smartcase)
`c`	Confirm each replacement
`e`	Suppress "no match" errors
`n`	Count matches (no replacement)

Common Examples

" Replace first occurrence on current line
:s/old/new/

" Replace all on current line
:s/old/new/g

" Replace all in entire file
:%s/old/new/g

" Replace all, case insensitive
:%s/old/new/gi

" Replace all, ask for confirmation on each
:%s/old/new/gc    (y/n/q/a/l at each prompt)

" Replace only in lines 10-20
:10,20s/old/new/g

" Replace in visual selection
:'<,'>s/old/new/g

" Count how many matches (no change)
:%s/pattern//gn

Live Substitution Preview

Enable real-time preview of replacements:

~/.config/nvim/lua/config/options.lua
vim.opt.inccommand = "split"   -- preview in split window
-- or
vim.opt.inccommand = "nosplit" -- preview inline only

Now as you type :%s/old/new, you see the changes highlighted in the buffer before pressing Enter.

Regex Patterns in Search

Neovim uses a variant of regex called "very magic mode":

" Standard (limited special chars)
/word

" Very magic: \v enables most regex chars without escaping
/\vword|other

" Examples with \v (very magic):
/\v\d{3}-\d{4}        → phone number pattern
/\vfunction\s+\w+\(   → function declaration
/\v(foo|bar)baz       → foo or bar followed by baz

" Capture groups in substitute:
:%s/\v(\w+), (\w+)/\2 \1/g    → swap "Last, First" to "First Last"

Substitute with Capture Groups

" Swap order: "LastName, FirstName" → "FirstName LastName"
:%s/\(\w\+\), \(\w\+\)/\2 \1/g

" In very magic mode (\v):
:%s/\v(\w+), (\w+)/\2 \1/g    (cleaner)

" Add quotes around a value:
:%s/\vkey: (\w+)/key: "\1"/g

" Replace function calls:
:%s/\vlog\((.{-})\)/console.log(\1)/g

Global Command (`:g`)

:g runs a command on every line matching a pattern:

" Delete all blank lines
:g/^$/d

" Delete all lines containing "TODO"
:g/TODO/d

" Copy all lines matching pattern to end of file
:g/pattern/t$

" Run a substitute on all lines containing "import"
:g/import/s/from '/from "

" Print all matching lines (like grep)
:g/error/p

" Reverse: run command on non-matching lines
:v/pattern/command   (or :g!/pattern/command)

Multi-File Search and Replace

Built-in Approach

" Open all JS files
:args **/*.js

" Do the replacement across all open args
:argdo %s/oldFunc/newFunc/ge | update

" Or for quickfix results from :vimgrep:
:vimgrep /pattern/ **/*.js
:cfdo %s/pattern/replacement/g | update

With Telescope (recommended — see Module 10)

<leader>sr   → Telescope live grep + replace (with plugin)