Notepad++ Search & Replace with Regular Expressions

Are you sure? Try selecting everything in the text and check In selection then do the 'Replace All'.

I suspect that your cursor was at the end of the file when you clicked 'Replace All' and the option was "Direction: Down". I do that myself sometimes without realising it only later!

You can use RegEx "capture groups" to specify sections you want to capture and keep, and replace the rest.

In Notepad++ capture groups are represented by brackets (( and )), and you can put their content into the "Replace" by using notation such as \1, \2, etc. for each capture group you added (in order of appearance).

So, change your search RegEx to (Dim.*)(As), which will find things as it did for you originally, but makes two capture groups. One before where you want to insert the ', and one after.

To this will find Dim variableName As Boolean as before, and the two capture groups would contain Dim variableName and As Boolean.

For the Replace field in Notepad++, use \1'\2; this will replace the matched text with the first capture group, then the ', followed by the second capture group.

Perform your replace, and Dim variableName As Boolean becomes Dim variableName 'As Boolean (etc).