There are four different ways to resolve conflicts interactively—two of which allow you to selectively merge and edit changes, and two of which allow you to simply pick a version of the file and move along.

If you wish to choose some combination of your local changes, you can use the “edit” command (e) to manually edit the file with conflict markers in a text editor (determined by the EDITOR environment variable). Editing the file by hand in your favorite text editor is a somewhat low-tech way of remedying conflicts (see the section called “Merging Conflicts by Hand” for a walkthrough), so some people like to use fancy graphical merge tools instead.

In order to use a merge tool, you need to either set the SVN_MERGE environment variable, or define the merge-tool-cmd option in your Subversion configuration file (see the section called “Configuration Options” for more details). Subversion will pass four arguments to the merge tool: The BASE revision of the file, the revision of the file received from the server as part of the update, the copy of the file containing your local edits, and lastly, the merged copy of the file (which contains conflict markers). If your merge tool is expecting arguments in a different order or format, you'll need to write a wrapper script for Subversion to invoke. After you've edited the file, if you're satisfied with the changes you've made, you can tell Subversion that the edited file is no longer in conflict by using the “resolved” command (r).

If you decide that you don't need to merge any changes, but just want to accept one version of the file or the other, you can either choose your changes (aka “mine”) by using the “mine” command (m) or choose theirs by using the “theirs” command (t).