How to remove multiple spaces, empty lines and, if possible, automatically clear the text of excess emptiness?

Question

Regular Expressions

Answer 1

In Sublime Text 3 we do the following:
1) Ctrl + H or through the Find->Replace panel . On Mac - Command + Alt + F
2) Turn on regular expressions (regular expression) - Alt + R. On Mac - Command + Alt + R
3) in the Find What field, write ^\n . Leave the Replace With field empty.
4) Click Replace All

Answer 2

Is there Notepad++?