A whole workout on deleting whitespace? It’s worth it…
You might want to start by enabling whitespace mode: M-x whitespace-mode
Let’s start with closing the gap between lines…
M-^ Join a line with the previous line C-x C-o Delete white space after current line up to next line.
What’s great about the above two commands is that the point can be anywhere on the line when you call them.
The next two commands aren’t quite so quick to use, the point needs to be in the whitespace you’re trying to delete.
M-SPACE Delete all spaces but one between two characters M-\ Delete all whitespace between two characters
Don’t forget the rectangle commands:
C-x r k Kills the rectangle between the point and the mark.
Find out more about how to use that command in this workout.
Lastly, removing line breaks. Use
C-M-% query replace regex Use C-q C-m or C-q C-j to find the line breaks.