How do I make the dot (.) in a Vim search pattern match newline characters too?

Explanation

In Vim's regex, . matches any character except a newline. To match any character including newlines, prefix it with \_ to get \_.. This lets you write patterns that span multiple lines — matching across line breaks that . alone would miss.

How it works

• . — matches any single character except newline
• \_. — matches any single character INCLUDING newline
• \_ can prefix any character class atom to add newline matching:
  • \_s — whitespace including newlines
  • \_w — word character or newline
  • \_[] — character class including newline

Examples

Match if followed by then with anything (including newlines) between:

/if\_.*then

Match a function signature that may span multiple lines:

/function\_s\+\w\+(\_.*)\n

Replace newlines between two patterns (join lines):

:%s/start\zs\_.*\ze end/ MIDDLE /

The \_ family

Tips

• \_.* is greedy and can match enormous spans of text — use \_.\{-} for non-greedy matching across lines
• This is Vim-specific syntax — PCRE uses the /s flag to make . match newlines; Vim uses the \_ prefix instead
• Combine with \zs and \ze to set match boundaries within a multi-line pattern
• :help /\_ documents the full collection of newline-inclusive atoms