Comparing and merging folders

When you start a folder compare operation, WinMerge displays this status window:

If the compare operation is quick, you might not notice the Progress window, which closes as soon as WinMerge displays the Folder Compare result. The Progress window shows the number of files and folders to be included in the operation, and the number compared so far. The progress bar graphically represents the Items compared.

	Note
	Because the files compares are usually of different sizes, the status data does not indicate the time used or remaining. For example, a 50/100 ratio does not necessarily mean that half of the compare operation time is expired.

You can click Stop to terminate the operation at any time before the compare operation finishes. The Folder Compare window is displayed with the results calculated at that time, omitting any uncompleted results.

The Folder Compare window looks and behaves slightly differently for recursive and nonrecursive compares:

In the Compare Folders window, files and folders are compared and divided into several categories. In each row, the category is clearly identified in the left column with one of these icons :

Identical text files

Identical binary files

Identical files (type undetermined)

Different text files

Different binary files

Different files (type undetermined)

Identical folders (in tree view only)

Different folders (in tree view only)

Left-only folders

Right-only folders

Left-only files

Right-only files

Skipped (filtered) directories

Skipped (filtered) files

Items that can't be compared; for example when another program has locked the file.

Aborted item. WinMerge did not finish comparing this item when the compare was stopped. The result is unknown.

You can use the mouse as well as keyboard and context menu shortcuts to navigate the Folder Compare window. You can also use the toolbar buttons. For example, the Next Difference button finds the next different file or folder and selects it.

	Note
	Unique files and folders are navigated in the same way as different ones.

You can select multiple files and folders. However, some operations (like Rename) are not available with multiple selections.

Use the navigation buttons (Next Difference, Previous Difference, and so on) to step through differences in the compared files. Use WinMerge functions to merge contents by copying, moving, or delete one or more files or subfolders.

By default, the WinMerge window displays a single File Compare or Folder Compare window.

In single compare mode, of you start a file or folder comparison while a Compare window is currently open, the current File Compare window is closed if there are no changes in either side. But if WinMerge detects unsaved changes (for example, if you have merged or edited a file),.WinMerge prompts you to save or discard your changes before opening a new File Compare window.

For example, in the next screen shot WinMerge gives you a chance to save changes detected in the right side file:

If you want to work with multiple compare operations simultaneously, consider setting (checking) the Enable multiple compare windows for Folder compare option, which is disabled by default. With this option enabled, you can open multiple File Compare windows without the intervening Save step.

When you open multiple Compare windows, they're displayed by default as individually resizeable child windows within the WinMerge window. This example shows a Folder Compare window — the File Compare window has similar child windows:

You can control the layering of multiple windows in either of two ways:

2.4.1. Using tabs with maximized Compare windows

Often, it's convenient to maximize your Compare window (by clicking its Maximixe button). The window then fills all the available space in the WinMerge window. The screen shot below shows a maximized Compare window.

When you maximize one Compare window, any other Compare windows are hidden, as shown in the preceding screen shot. To access those windows, you could return to the default view by clicking the Restore button. A better solution is to enable tabs by setting (checking) View → Tab Bar.

When you display the Tab bar, each Compare window has a tab that shows the filenames of the two compared files. Now, you can easily identify and display any available Compare window, and the selected Compare window remains maximized:

The most common file operation in the Folder Compare window is copying files from side to side. There are several forms of the WinMerge copy function: all of them copy only files that are different, because copying identical files is of no use in merging. The copy functions are available in the context menu, in the WinMerge menu, and in the toolbar:

3.1.1. Context menu Copy shortcuts

In the Folder Compare window's context menu, the Copy item has a submenu with four shortcuts:

• Left to Right and Right to Left copy the selection (or just the items in the selection that can be copied) from one side to the other. In the example, the suffix (2 of 4) indicates that only the two files that are different will be copied; the identical files will not. These shortcuts available only if any of the files you select is different: if you select only identical files, the shortcuts are unavailable.

• Left to... and Right to... enable you to specify a copy target directory in your system, instead of a compared folder. When the Browse for Folder dialog opens, navigate to the target directory on your system (or create a new target folder) and click OK.

You can use the Delete context menu item to delete selected items in either or both sides. Like other file operations, Delete has a submenu with Left, Right, and Both shortcuts.

Warning

We highly recommend that you keep the Send deleted files into Recycle Bin option enabled See Options and configuration), so that you can undo deletions in case of accidents. In addition, you should keep Recycle Bin enabled: the WinMerge option does not work if you disable the Recycle Bin in Windows. Again, you cannot undo file or folder deletion unless you use both the WinMerge Send deleted files into Recycle Bin option and the Windows Recycle Bin!

To rename a file or folder, choose Rename in its context menu or press F2. Then change the name in the edit box and press Return, or press Esc to cancel. You can only rename a single file or folder. Note that renaming changes items in both sides: it is not currently possible to rename an item on just one side.

In the context menu, you can use either Open Left and Open Right, depending on which side you want to operate on. Each Open menu item has a submenu with these shortcuts:

The context menu Copy Pathname and Copy Filenames shortcuts copy the pathname or filename of selected items to the Windows clipboard. You can then paste the copied information into a file or application, for example to create a list of changed files or a change log.

To protect the files and folders on either side of a compare from changes, enable the File → Left Read-only or File → Right Read-only check box.

	Important
	Setting the read-only option protects files and folders only in the current compare view; it does not affect their Windows file attributes.

This protected status is inherited by files that you open in the folder compare. For example, if you compare two folders, set one side read-only, and open two files for comparing, the open file on the protected side is write-protected. Similarly, you cannot copy a file from the unprotected side to the protected side.

The RO code in the left or right side's pane in the status bar (near the bottom right of the window) indicates that the side is currently read-only.

A full refresh of large folders can take a long time. In WinMerge 2.2 and earlier, you always had to do a full refresh to update files after editing them outside WinMerge. Starting in Version 2.4, WinMerge can refresh just selected items: choose Refresh from the context menu or View → Refresh Selected from the main menu.

Use the context menu Zip menu item to create a new archive file containing the items you select.

	Note
	Archive support requires that you have installed the WinMerge 7-Zip plugin.

The Zip menu item has a submenu with four shortcuts:

When you select one of the Zip shortcuts, the Save As dialog prompts you for the archive filename and type. WinMerge cannot add files to existing archive files: it always creates a new archive file.

	Tip
	WinMerge can compare the contents of archive files that have the same name on both sides: WinMerge looks for the Original and Altered subfolders, and compares the contents of those two folders.

If a folder compare includes the contents of an archive file, any changes made to the included files in WinMerge (for example, using an Open file operation to edit the file) are saved in the archive file. But you cannot update archive contents by using the WinMerge Copy, Move, or Delete file operations. Instead, create a new archive file using one of the Zip shortcuts.

Even though a nonrecursive folder compare does not include the contents of subfolders, the subfolders themselves are listed as files in the result. Similarly, the compared folder's parent folder is listed as a file at the top of the table. By opening these folders directly in the Folder Compare window, you can selectively browse a directory tree. This approach — comparing just the subdirectories you are interested in — can be more efficient than performing a recursive compare on the entire directory tree.

In WinMerge 2.6 and earlier, you could not browse to unique folders (folders that exist only in one side of a compare result), because WinMerge cannot compare an existing folder to a non-existing folder. To copy anything from a unique folder in WinMerge, you had to first create a copy of the entire folder structure.

However, you might prefer not to copy the whole folder structure. Starting in Version 2.8, WinMerge provides an alternate way to create a new, empty folder instead. This enables you to copy just the elements you want from the original, unique folder to the created empty folder. This procedure demonstrates:

The View menu contains these shortcuts to show or hide types of items. Enable (check) a menu option to show the item; disable it to hide the item.

The rows in the Folder Compare window are ordered according to the sort order of a particular column. This sort column is indicated by a small arrow in its heading. The arrow points up if the column is sorted in ascending order, down if descending. The Folder Compare example at the top of this topic is sorted by the Filename column, in ascending order.

To choose another order column, simply click in that column's heading. The selected column is set to its default sort order and all the rows are reordered by that column's sort order.

To change the sort direction of a column that is already the sort column, click in its header again. That is, clicking in a sort column header reverses its order (toggling between ascending and descending order).

To modify the columns that are displayed in the Folder Compare window:

The following columns in the Display Columns dialog are displayed by default in the Folder Compare window:

The following additional columns are available in the Display Columns dialog:

You can quickly hide one or more selected items by using the Hide Items context menu shortcut. The items remain hidden until you refresh the view (press F5) or click View → Show Hidden Items.

	Tip
	Get to know Hide Items: it can save you a lot of time by eliminating items that you already handled, or that are not currently of interest, from the view. For example, you might hide files after merging them, making it easier to see what items are left to merge.