In Git GUI I can select parts of a diff and stage just those lines or chunks. How would I do the opposite, as in roll back changed lines in a file. Usually these are accidental white space changes I just want to revert out but still stage/commit other parts of the same file.
For Git Gui: First, click Rescan to scan for the modified file. Next, click the icon to the left of the filename to stage all modifications for commit. Then, right click on the debug line and chose Unstage Line From Commit.
The above information from: http://nathanj.github.com/gitguide/tour.html