Replacing multiple blank lines with one blank line using RegEx search and replace

Question

I have a file that I need to reformat and remove \"extra\" blank lines.

I am using the Perl syntax regular expression search and replace functionality of UltraEdit a

Answer 1

See this thread for what's causing the problem. As I understand it, UltraEdit regexes are greedy at the character level (i.e., within a line), but non-greedy at the line level (roughly speaking). I don't have access to UE, but I would try writing the regex so it has to match something concrete after the last blank line. For example:

search:   (\r\n[ \t]*){2,}(\S)
replace:  $1$2

This matches and captures two or more instances of a line separator and any horizontal whitespace that follows it, but it only retains the last one. The \S should force it to keep matching until it finds a line with at least one non-whitespace character.

I admit that I don't have a whole lot of confidence in this solution; UltraEdit's regex support is crippled by its line-based architecture. If you want an editor that does regexes right, and you don't want to learn a whole new regex syntax (like vim's), get EditPadPro.