git - trim whitespace

Question

I've accidentally put some whitespace in my initial commit - it shows up red in git diff --color. What's the best way to get rid of the existing whitespace and how can I avoid this happening again?

I am not necessarily looking for a built-in git command. Any external program available for free on Ubuntu would also be welcome.

Answer 1

To trim trailing whitespace on all files in the current directory, use:

sed -i 's/[[:space:]]*$//' *

To warn about future whitespace errors (both trailing spaces and spaces before tabs), and to fix whitespace errors in patches, add the following code to your gitconfig file:

[core]
    whitespace = trailing-space,space-before-tab
[apply]
    whitespace = fix

Answer 2

core.whitespace instructs git to flag certain whitespace problems:

• trailing-space warns about whitespace at the end of a line or at the end of a file
• space-before-tab warns when there is a space before a tab used for indentation

apply.whitespace is used when applying a patch. It checks for whitespace errors (the ones listed above, in core.whitespace) and applies the patch after attempting to fix them (i.e., remove them).

These options go in ~/.gitconfig -- that is, a .gitconfig file at the root of your user's home directory (typically /home/user/.gitconfig on Linux, /Users/user/.gitconfig on Mac OS X, and I don't know where on Windows but I suppose somewhere in C:\Documents and Settings\user).