How to substitute text across line breaks?

Question

I would like to reformat code in an entire file from this brace style:

if (condition)
{
    body;
}

… into this brace style¹:

if (condition) {
    body;
}

The bulk of the task should be accomplishable by relocating the opening braces. I would like to do something like

:%s/^M *{$/ {/

… but substitutions don't seem to work across line breaks.

Is there a way to make substitutions work across line breaks? If not, what is the next-best solution that does not involve an external command or plugin? (I'm more interested in text-editing technique than in specialized programming tools.)

---

¹ No flame wars about the choice of brace style, please!

Answer 1

You can use \n to do substitutions across multiple lines. There are also special characters which start with \_ that are the same as their normal counterparts, except it adds newline to their character class. For instance, \_s is the same as \s, except it also matches newline characters. Here is your search and replace statement with this special character:

:%s/\n *{$/ {/

Of course, you can make the regex more specific, since this one may match more than you want.

References:

• http://vim.wikia.com/wiki/Search_across_multiple_lines
• :help \_