Emacs: Newline Convention

Newline Character in Emacs Buffer

in emacs buffer, newline character is always Line Feed (ASCII 10, "\n"), on any Windows, Mac, Linux.

to insert it literally, see Emacs: Insert Tab or Newline

File Newline Convention in Windows, Mac, Linux

Different operating systems use different characters for newline (aka end-of-line char, eol char), and or use a combination of them to represent a single newline.

Newline is indicated by 1 or 2 control characters.

Note: Mac OS X prefers LF, but accept the Mac OS Classic's CR too.

ASCII Characters for Newline

The following characters are used for newline.

• ASCII Characters

Why is emacs showing ^M

If emacs displays many ^M (CR, codepoint 13) that probably means there's inconsistent line ending in the file.

Find out what char is ^M ^J ^L

• Emacs: Get Char Info. Name, Position, Font, Encoding, Syntax, Etc

How to delete ^M

1. Goto beginning of the file, then Alt+x query-replace, then insert the Carriage Return char by Ctrl+q Ctrl+m for the find string. For replacement string just press Enter for empty string.
2. Alt+x set-buffer-file-coding-system, then type one of: {mac, dos, unix}. Then, save the file.

Automatically Add Newline at End of File

require-final-newline

Variable.

Whether to add a newline automatically at the end of the file.

• t means do this only when the file is about to be saved.
• 'visit means do this right after the file is visited.
• 'visit-save means do it at both of those times.
• Any other true value means ask user whether to add a newline, when saving.
• nil means don't add newlines.

mode-require-final-newline

Variable.

same as require-final-newline, but used by some Major Mode

💡 TIP: some system tool or protocols expect a newline at the end of file.

🛑 WARNING: Do not manually do find replace to change newline character in a buffer, because after you save the file, a unexpected newline character may be quietly added because of require-final-newline.