Discard changes in one single line

Question

I've noticed that in Tower (Git client for the Mac) the user can discard changes even line by line. I wonder how could this be done using the command line? or maybe is something special of Tower?

I frequently find myself in this case:

@@ -391,7 +392,7 @@ extern BOOL validateReceiptAtPath(NSString *path);         NSURL *url = [self fileURL];         if (url != nil) {                 NSRect readFrame = [self _readPreferenceOfFileAtURL:url]; -                +                 for (NSScreen * screen in [NSScreen screens]) {                         NSRect screenVisibleRect = [screen visibleFrame];                         ... 

See how I have one + and one - ? I would like to discard it so my commit has the minimum changes (hence less possibilities of conflicts and easier review)

:)

Answer 1

This is called interactive staging and can be done using git add -i or git add -p. See the git-add manpage, pro git and the Git Community Book for more information.

EDIT:

To interactively unstage a file, you can use:

git checkout -p HEAD 

Also see this SO question: Undo part of unstaged changes in git

Answer 2

To undo hunks use

git reset --patch 

It’s a very hidden feature. You can stage hunk by hunk with git add --interactive, but you can’t unstage this way. git add also features the option --patch which is like --interactive, but goes directly to the “patch” menu point (otherwise you have to hit pENTER).

git reset does not mirror the --interactive option, but has --patch.