How to search and replace carriage return with space

edit

I am using ver. 5.2.7.2 and cannot make this work at all. In a file like this........

ANDERSON, ANDREWS ARMSTRONG BALLANTINE BARBOUR BARBOURYOUNG BRADLEY BROWN CAMPBELL CARSON CHADWICK CHRISTIE CLARKE COCHRANE COLEHAMILTON

I am trying to add a comma at the end of each line

Suppose you mean switching to new paragraph. You can only replace all the paragraph shifts in a complete selection.
To do so
- select the range
- open 'Find & Replace'
- enter $ (nothing else) into 'Search'
- enter the replacement (in your case a space) into 'Replace'
- Check if options 'Current selection only' and 'Regular expressions' are checked
- hitt 'OK'

If your question was about hard line breaks: You find them with \n and you can combine this with other RegEx elements.