git diff - show me line ending changes?

My editor is changing the line endings of my source files. When I do git diff, I see the same line twice -- once with - and once with + -- with no visible difference.

How do I get git diff to show me what this change actually was?

First, make sure you're using the coloured output (e.g. with git diff --color) and that you've enabled whitespace highlighting with (e.g.)

git config color.diff.whitespace "red reverse"

This might not work in all cases, however, as git doesn't appear to highlight trailing whitespace for removed lines. To see whitespace that you've deleted, simply use

git diff -R

to put the whitespace on the 'added' side of the comparison, where it does get highlighted.

For more detail, see the answers at this SO question.

You can see line-ending difference with the following command.

git diff | cat -v

Then "^M" is printed for CRLF (DOS) ending, nothing for LF (Unix) ending.

Apparently git diff is doing the right thing, printing CR and LF characters for CRLF ending. But because CR is consumed by the console, we cannot see it. By using cat -v, we can make it visible.

One way to see whitespace changes is to do a character-by-character "word diff" with

git diff --color --word-diff-regex=.

This highlights all whitespace changes everywhere in lines. Removed whitespace is wrapped in [- and -] and added whitespace in {+ and +}.

Alternatively, as suggested by Alex

git diff --color --ws-error-highlight=new,old

highlights all whitespace changes at the ends of lines.

git diff --ws-error-highlight=new,old

highlights whitespace diffs in changed lines.

A graphical diff tool will show you the change better -- try git difftool.

Use meld, and set the preferences to show whitespace. (Edit -> Preferences -> Show Whitespace.)

Other graphical tools probably have similar options -- @Cotton's answer+comment tells you how to do this with vimdiff.