Path Finder 7 includes FolderSync, a folder comparison and syncing engine written from the ground up by Cocoatech. It can be accessed in two ways, depending whether you work in Single or Dual Pane mode.
If you are in Single Pane mode, select two folders. Control-click or right-click the selected folders, then select FolderSync from the contextual menu. You can do the same from the action menu (if you placed the Action item on window toolbar). Note that this menu item will not appear if you've selected more than two folders. This situation is shown in the picture below.
If you are in Dual Pane mode, select one folder in each pane. From the main menu, select Commands > FolderSync…. (You can assign a key shortcut to this command in the Path Finder preferences, then Features>Keyboard.) Note that this menu item will be disabled if you've selected more than one folder in each pane. This situation is shown in the picture below.
A new window appears, where all folder comparison and synchronisation takes place. By default, the operation starts in Compare mode, comparing two folders and marking their differences. Depending on folders sizes and structure, this step can take a while. While it is ongoing, you'll see Analyzing… in the bottom of the window. The comparison analyzation process is shown in the picture below.
Once the comparison is done, the results will be shown. Path Finder hierarchically displays differences in two folders. You can see an example in the picture below.
When showing folders differences, Path Finder uses different colors to mark items which are different. You can see what these colors mean if you click Colors… button. In the sheet that appears, you can change default colors to your linking. You can see this in the picture below.
Once you compared folders, you would probably like to do actual synchronisation. A couple of predefined operations are available: Compare, Update Left, Update Right, Update Both, Mirror to Left, Mirror to Right. In the picture below, you can see an example of Path Finder showing which operations are needed to perform Update Both synchronisation, as well as information how many items will be added, updated and deleted.
What each of these predefined operations do can be seen if you click Presets… button. The picture below shows what Update Both actually does.
Using the available buttons, you can redefine behavior of those operations to whatever seems more reasonable and logical to you. You can also define filters for which items to include and exclude from folder comparison and syncing. Filter editors are accessed by clicking the Edit filters… button (you have to enable filters first by checking Filter items checkbox.) An example of it is shown in the picture below.
Once you are satisfied with the shown result, click Sync button to begin the syncing operation. After some processing, the FolderSync window will disappear and the syncing operation will start. It acts the same way as other file operations (copy, move, delete…) and you can monitor its progress in the file operation progress window or Progress toolbar item popup, as shown in the picture below.