---
title: No Newline at End of File
teaser:
tags: unix,vim,git
author: Mike Burns
published_on: 2013-11-15
---

Have you ever seen "No newline at end of file" in your git diffs? Us, too.

    ~/.dotfiles% git diff
    diff --git a/vimrc b/vimrc
    index 7e31913..a8b5f95 100644
    --- a/vimrc
    +++ b/vimrc
    @@ -2,4 +2,4 @@
     let configs = split(glob("~/.vim/configs/*"), "\n")
     for filename in configs
       execute 'source ' filename
    -endfor
    +endfor
    \ No newline at end of file

Why does this happen and what does it mean?

## Try it in your shell

Here I have made a text file and, by definition, a non-text file:

    ~% echo foo > text-file
    ~% od -c text-file
    0000000   f   o   o  \n
    0000004
    ~% wc -l text-file
    1 text-file
    ~% echo -n foo > binary-file
    ~% od -c binary-file
    0000000   f   o   o
    0000003
    ~% wc -l binary-file
    0 binary-file

If you open each file in vim, they will display similarly. The intuition behind
what vim is doing is "separate each line with a line break", which is different
from "display each `\n` as a line break".

However, the `binary-file` will cause vim to display `[noeol]` in its status
line (with the default status line).

## History lesson

This comes from [an old C decision][oldc] that has been passed down through Unix
history:

> A source file that is not empty shall end in a new-line character, which shall
> not be immediately preceded by a backslash character.
>
> Since this is a "shall" clause, we must emit a diagnostic message for a
> violation of this rule.

[oldc]: http://gcc.gnu.org/ml/gcc/2003-11/msg01568.html

So, it turns out that, according to [POSIX][posix], every text file (including
Ruby and JavaScript source files) should end with a `\n`, or "newline" (not "a
new line") character. This acts as the [`eol`][eol], or the "end of line"
character. It is a line "terminator".

[posix]: http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap03.html#tag_03_206
[eol]: http://stackoverflow.com/a/16224292/303882

## Following the rules in your editor

You can make sure you follow this rule easily:

* For **Vim** users, you're all set out of the box! Just don't change your `eol`
  setting.
* For **Emacs** users, add `(setq require-final-newline t)` to your `.emacs` or
  `.emacs.d/init.el` file.
* For **Android Studio**, **RubyMine**, **PyCharm**, and other **IntelliJ**,
  set "Ensure line feed at file end on Save" under "Editor."
* For **Atom**, you're also all set out of the box. Keep that via the
  Whitespace plugin.
* For **VS Code**, set `"files.insertFinalNewline": true`.
* For **Sublime**, set the `ensure_newline_at_eof_on_save` option to `true`.
* For **TextMate**, you can install the [Avian Missing
  Bundle](https://github.com/elia/avian-missing.tmbundle#strip-trailing-whitespace-on-save)
  and add `TM_STRIP_WHITESPACE_ON_SAVE = true` to your `.tm_properties` file.

## What's next

If this satisfied your curiosity, you might also enjoy:

* [${VISUAL}ize the Future][visual]
* [How `grep` Got Its Name][grep]
* [Onramp to Vim][onramp]

[visual]: https://thoughtbot.com/blog/visual-ize-the-future/
[grep]: https://thoughtbot.com/blog/how-grep-got-its-name/
[onramp]: https://thoughtbot.com/upcase/onramp-to-vim