Update the working copy with respect to the repository.

Update brings your working copy up-to-date by applying changes from the repository, merging them with any changes you have made to your working copy if necessary. When the working copy was first created, its contents exactly reflected a specific revision of the repository. The VCS remembers that revision so that it can keep careful track of where you started making your changes. This revision is often referred to as the parent of the working copy, because if you commit changes from the working copy, that revision will be the parent of the new changeset.^[9]

Update is sort of like the mirror image of commit. Both operations move changes between the working copy and the repository. Commit goes from the working copy to the repository. Update goes in the other direction.