# Neovim Searching and Replacing

**Search and replace** are fundamental for editing large files and maintaining consistency. Neovim uses standard regex patterns.

## Basic search

`/pattern` — search forward, `?pattern` — search backward. Type pattern, press `Enter` to jump to first match.

`n` — next match in same direction, `N` — previous match (reverse direction). `*` — search for word under cursor forward, `#` — search backward.

Clear last search highlighting: `:nohlsearch` or `:set hlsearch` / `:set nohlsearch` to toggle.

```vim
/function        " search for "function"
n                " next match
N                " previous match
*                " search word at cursor
```

## Case-insensitive search

`:set ignorecase` — makes search case-insensitive. `:set smartcase` — ignores case unless you use uppercase in pattern.

```vim
:set ignorecase
/CONST           " finds const, Const, CONST
```

Inline toggle: append `\c` to pattern for case-insensitive, `\C` for case-sensitive.

```vim
/Pattern\c       " search case-insensitive
```

## Find and replace

`:s/old/new` — substitute in current line, `:s/old/new/g` — all occurrences in line.

`:%s/old/new` — first occurrence per line in file, `:%s/old/new/g` — all occurrences in file.

`:%s/old/new/gc` — replace with confirm (shows each match, prompt `y`/`n`). `:%s/old/new/i` — case-insensitive.

```vim
:s/const/let/     " first per line
:s/const/let/g    " all in line
:%s/old/new/g     " all in file
:%s/foo/bar/gc    " confirm each
```

## Regex patterns

Patterns support regex. `.` matches any char, `*` is 0 or more, `+` is 1 or more, `?` is 0 or 1.

`^` — line start, `$` — line end. `\<` — word boundary start, `\>` — word boundary end.

Groups: `\(pattern\)` captures, `\1` refers to first group.

```vim
:%s/\<word\>/new/g     " whole words only
:%s/^/> /g             " add "> " to line start
:%s/\(.\)\(.\)/\2\1/g  " swap adjacent chars
```

## Substitution with addresses

`:10,20s/old/new/g` — replace in lines 10–20. `:.,+5s/old/new/` — replace in current and next 5 lines.

`:'<,'>s/old/new/g` — replace in visual selection (select text, type command).

## Search within selection

Visual select, then `:` auto-fills `:'<,'>`. Type the substitute command.

```vim
v5j                    " select 5 lines
:s/old/new/g           " replace in selection
```

Quick workflow: search with `/`, view context, `:set hlsearch` highlights all, then `:%s/old/new/gc` to replace with confirmation.