You need to undo changes made in a commit

All you need to do here is to call the log, get the ObjectID of the commit you want to undo and call:

git revert ObjectID

Let's go back to the log:

Figure 12.3: Log, starting point

Now let's revert the commit that added the hello message:

git revert c507abf

Because I reverted a change in the middle of the branch, it's no surprise that I run into a merge conflict:

Figure 12.4: Merge conflict

To solve this I will call git mergetool, invoking the tool I set up in Chapter 4, Merging, Pull Requests, and Handling Merge Conflicts. Kdiff3 is smart enough to fix all the conflicts without my help:

Figure 12.5: Kdiff3 fixes the conflicts for me

Sure enough, when we open Program.cs the Hello World is gone:

Figure 12.6: Program.cs after revert