replace all line breaks not precede by a period with a regular expression?

Question

Is is possible to select only line breaks that are not preceded by a period using regular expressions ? I am editing subtitles files for students. To make the printed version dead tree friendly I am trying to replace all the line breaks not preceded by a period or question mark with a space.

option 1
select all the line breaks not preceded by a period or question mark regex [a-z]\n works for that but then it of course selects the last letter of the word before the line break. -> Is it possible to somehow save and insert the last letter of the word before the line break and insert that together with a space using regular expressions or do I have to write a script for that (say php)

option 2
Select only line breaks that are preceded by a character. I tried looking into lookbehind.

While writing this question the solution hit me. To select a line break precede by a character do (?<=[a-z])\n and then replace with a space.

I searched stack overflow and could not really find what I was looking for. I hope I will not offend anybody by posting the question and solution at the same time. It might help someone else in the future.

Answer 1

I have had this problem recently, I solved it like this:

search:

"(?<!\.|\?)(\r\n)+([^?\.]+)"

replace: (Be careful! There is a space!!)

" $2"


(?<!\.|\?) -> There can't be ./?
(\r\n)+ -> one or more newlines 
([^?\.]+) -> selects everything of the new line except ?/. 

" $2" -> second capture group with SPACE before.

I used Regex Buddy, if it doesn't work for you, I can try to convert it for you to another programming language using Regex Buddy.