Clean and keep line breaks

[jackwebso]

Hello,

I want to keep line spaces in comments but clean more then 2 after each.

Example:

$sentence="This is my first sentence
This will be in a new row
This will be too in a new row but not separated with 3line breaks just with

one

";
And i want to output just this:

$sentence="This is my first sentence
This will be in a new row

This will be too in a new row but not separated with 3line breaks just with
one
";
Please Help

Thanks in Advance