How to delete empty lines in a file using Emacs?

Question

In Emacs, how to remove all empty lines (including tabs and spaces) in file?

Can Mx replace-regexp do the trick?

I can find the empty lines with regexp: ^[st]*$ , but don't know how to replace it by deleting.

Answer 1

Mx flush-lines RET ^[[:space:]]*$ RET可能是规范的方法。

Answer 2

^ and $ just match starts and ends of lines, not the actual end-of-line characters. You have the explicitly type the newline in the expression to replace it.

To achieve your goal, replace-regexp

^[[:space:]]*^J

with nothing (empty text). To enter ^J , first press Control and Q, then Control and J. In the entry field, this shows up as an actual line change.