Git replacing LF with CRLF

Question

On a Windows machine, I added some files using `git add`. I got warnings saying: LF will be replaced by CRLF What are the ramifications of this conversion?

Accepted Answer

These messages are due to an incorrect default value of `core.autocrlf` on Windows.

The concept of `autocrlf` is to handle line endings conversions transparently. And it does!

Bad news: the value needs to be configured manually.

Good news: it should only be done one time per Git installation (per project setting is also possible).

How `autocrlf` works:

```
core.autocrlf=true:      core.autocrlf=input:     core.autocrlf=false:

repository               repository               repository
      ^      V                 ^      V                 ^      V
     /        \               /        \               /        \
crlf->lf    lf->crlf     crlf->lf       \             /          \
   /            \           /            \           /            \
```

Here `crlf` = win-style end-of-line marker, `lf` = unix-style (also used on Mac since Mac OS X).

(pre-osx `cr` is not affected for any of three options above.)

When does this warning show up (under Windows)?

– `autocrlf` = `true` if you have unix-style `lf` in one of your files (= RARELY), – `autocrlf` = `input` if you have win-style `crlf` in one of your files (= almost ALWAYS), – `autocrlf` = `false` – NEVER!

What does this warning mean?

The warning "LF will be replaced by CRLF" says that you (having `autocrlf`=`true`) will lose your unix-style LF after commit-checkout cycle (it will be replaced by windows-style CRLF). Git doesn't expect you to use unix-style LF under Windows.

The warning "CRLF will be replaced by LF" says that you (having `autocrlf`=`input`) will lose your windows-style CRLF after a commit-checkout cycle (it will be replaced by unix-style LF). Don't use `input` under Windows.

Yet another way to show how `autocrlf` works

```
1) true:             x -> LF -> CRLF
2) input:            x -> LF -> LF
3) false:            x -> x -> x
```

where x is either CRLF (windows-style) or LF (unix-style) and arrows stand for

```
file to commit -> repository -> checked out file
```

How to fix

The default value for `core.autocrlf` is selected during Git installation and stored in system-wide gitconfig (`%ProgramFiles(x86)%\git\etc\gitconfig` on Windows, `/etc/gitconfig` on Linux). Also there're (cascading in the following order):

– "global" (per-user) gitconfig located at `~/.gitconfig`, yet another – "global" (per-user) gitconfig at `$XDG_CONFIG_HOME/git/config` or `$HOME/.config/git/config` and – "local" (per-repo) gitconfig at `.git/config` in the working directory.

So, write `git config core.autocrlf` in the working directory to check the currently used value and

– `git config --system core.autocrlf false` # per-system solution – `git config --global core.autocrlf false` # per-user solution – `git config --local core.autocrlf false` # per-project solution

Warnings

– `git config` settings can be overridden by `gitattributes` settings. – `crlf -> lf` conversion only happens when adding new files, `crlf` files already existing in the repo aren't affected.

Moral (for Windows):

- use `core.autocrlf` = `true` if you plan to use this project under Unix as well (and unwilling to configure your editor/IDE to use unix line endings), - use `core.autocrlf` = `false` if you plan to use this project under Windows only (or you have configured your editor/IDE to use unix line endings), - never use `core.autocrlf` = `input` unless you have a good reason to (eg if you're using unix utilities under Windows or if you run into makefiles issues),

PS What to choose when installing Git for Windows?

If you're not going to use any of your projects under Unix, don't agree with the default first option. Choose the third one (Checkout as-is, commit as-is). You won't see this message. Ever.

PPS: My personal preference is configuring the editor/IDE to use unix-style endings, and setting `core.autocrlf` to `false`.

Update(2022)

Since 2018, git can --renormalize repo fixing the existing line endings as required.

Git replacing LF with CRLF

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