Multiline search and replace in Visual Studio

Today I had to add a new HttpModule to A LOT of web.configs. Adding it manually would be too tedious, so I had to figure out how to search for a single line in Visual Studio 2010 and replace it with two lines of text. If I could only find a way to search for some text, and replace it with several lines of text!

Google turned up some hints about the Regex search, but no apparent solutions. After playing around a bit with the regex search in Visual studio, I found that it supports multiline text in both the search and replace strings.

When you're using "Find and Replace" in Visual Studio you can enable Regular Expressions, under "Find options", as shown in the screenshot. The regular expressions let you represent newlines in the search or replace fields, by using a \n. Cool! I've included an example below the image.

But beware, when you enable regular expressions you need to escape special characters, in my case < and >,  with a backslash. Your "Find" statement will be interpreted as a regular expression. Check out the MSDN page on regular expressions in Visual Studio to learn more about which characters are special and which are not.

Update Sep. 2012: This post deals with Visual Studio 2010. Regular expressions have changed in VS 2012, as you'll see from the link above. See the comments on this post for a new example of multiline search and replace for both VS 2010 and VS 2012.

In my case, I wanted to add a new module directly after the WIF SessionAuthenticationModule. I've shortened the config lines, for space and readability. To match the config line I had to escape < and > which have special meaning in a regex.

\<add name="SessionAuthenticationModule" ... PublicKeyToken=31bf3856ad364e35" /\>

And you want to replace it with itself, followed by a new line of config (the \N represents the newline):

<add name="SessionAuthenticationModule"... />\n <add name="BrandNewModule" ... />

This neatly replaced the line of config with the two lines of config I was hoping for:

<add name="SessionAuthenticationModule"... PublicKeyToken=31bf3856ad364e35" />
<add name="BrandNewModule" ... />

Easy huh?

***Update***
Mr. F pointed out a better solution in his comment on this post — tagging expressions. Just now, I had to add a new appsetting to a lot of web.configs so I had to give it a try! In the "Find what:"

{\</appSettings\>}

and in the "Replace with:"

<add key="newsetting" value="somevalue"/>\n  \1

Even cooler! Thanks F! (We both know who you are..)