17. Frequently asked questions

17.1. General questions

17.1.1. Why is there two executable files, WinMerge.exe and WinMergeU.exe?
17.1.2. That splash screen is annoying, how do I turn it off?
17.1.3. When wanting to compare directories, I cannot select a directory in Browse?
17.1.4. Does WinMerge support merging three files? Sometimes it is called 3-way merge, where one file is ancestor. This would be useful for version control!
17.1.5. Do you have any plans to support other operating systems than Windows?
17.1.6. There is no CVS integration?!
17.1.7. What is MRU (list)? What it means?
17.1.8. Can WinMerge open Open Office files?

17.1.1. Why is there two executable files, WinMerge.exe and WinMergeU.exe?

  • WinMerge.exe is ANSI executable which works in all 32-bit Windows systems. It does not have Unicode support.

    Internally, it stores only ANSI characters (256 possibilities). If you open an Unicode (65536 possible characters) file, the characters must be converted to the ANSI character set. Conversion can be approximative (accents are lost), or impossible (characters appear as "?").

    WinMerge.exe can neither open files when filename is not writeable in the current ANSI set.

  • WinMergeU.exe is Unicode enabled executable which works in Windows NT4, Windows 2000 and newer systems.

17.1.2. That splash screen is annoying, how do I turn it off?

From menu, select Edit->Options...->General->Disable Splash Screen

17.1.3. When wanting to compare directories, I cannot select a directory in Browse?

Are you trying to select a directory by clicking on it in the upper part of the Open File dialog ? The Open File dialog will then open it, and you have to push Ok again to get out.

17.1.4. Does WinMerge support merging three files? Sometimes it is called 3-way merge, where one file is ancestor. This would be useful for version control!

Unfortunately not. We acknowledge it would be good feature but have no plans to implement it in near future. This can be somewhat work-arounded using two WinMerge instances.

17.1.5. Do you have any plans to support other operating systems than Windows?

Not currently. If somebody wants to help/work with cross-platform support (using wxWidgets for example) we are interested of course.

17.1.6. There is no CVS integration?!

Which kind of CVS integration WinMerge should have? Adding CVS client features to WinMerge is questionable since there are many good CVS clients already. Conflict file resolution is feature we are planning to add in future releases.

17.1.7. What is MRU (list)? What it means?

MRU is the abbreviation for "Most Recently Used", and means the history lists in Open-dialog thats containing 20 last used files/paths per side.

17.1.8. Can WinMerge open Open Office files?

Yes, enable Detect archive type from file signature option in Archive Options.

17.2. Questions about binary files

17.2.1. WinMerge says "Binary files are different", but I am not comparing binary files?
17.2.2. WinMerge cannot compare registry files (*.reg)?
17.2.3. WinMerge tells my files are binary files even when they are not?
17.2.4. I cannot merge binary files?

17.2.1. WinMerge says "Binary files are different", but I am not comparing binary files?

If you are using WinMerge.exe (not WinMergeU.exe), then your files may be Unicode files. WinMerge.exe cannot handle Unicode files. Please try comparing files with WinMergeU.exe if you have Windows NT4, Windows 2000 or newer Windows version.

17.2.2. WinMerge cannot compare registry files (*.reg)?

Windows registry files (*.reg) are Unicode files (UTF-16 or UCS-2) -- see previous answer.

17.2.3. WinMerge tells my files are binary files even when they are not?

There is one or more zero-bytes in your file(s). If WinMerge finds zero-bytes from files it detects files as binary files. You can try to remove those zero-bytes from files. Or open files with DisplayBinaryFiles -plugin. DisplayBinaryFiles -plugin allows viewing binary files but does not allow saving changed files.

17.2.4. I cannot merge binary files?

WinMerge does not include binary file viewer/editor so WinMerge can only show if binary files are identical or different.

17.3. Questions about editor

17.3.1. Some characters are cut in half?
17.3.2. I would like to see the line numbers?
17.3.3. I see question marks instead of letters in files?
17.3.4. I cannot select proportional fonts for editor?
17.3.5. What means delaying of (automatic) rescan? Why it is needed?
17.3.6. Can I print files from editor?

17.3.1. Some characters are cut in half?

Try selecting a different font from menu View->Select Font...

17.3.2. I would like to see the line numbers?

WinMerge shows current line in editor statusbar. WinMerge cannot show in-editor linenumbers. That is one feature we might consider for future releases.

17.3.3. I see question marks instead of letters in files?

This is what we call a "lossy" conversion.

For Unicode files (UCS-2, UTF-8), use WinMergeU.exe.

For ANSI files, this is probably due to code-page problem. If "Use codepage info" is selected from Options, turn that off and see if it helps.

17.3.4. I cannot select proportional fonts for editor?

Unfortunately WinMerge 2.0 and 2.2 supports only non-proportional fonts.

17.3.5. What means delaying of (automatic) rescan? Why it is needed?

When Automatic Rescan is enabled WinMerge delays rescanning while user edits files. So there is no rescanning happening when user types text but shortly after user has finished typing. Without this delaying WinMerge would do rescan after every typed letter and editing files would become slow. This delaying especially improves editing of bigger files which can take several seconds to rescan.

17.3.6. Can I print files from editor?

Unfortunately printing is not supported. This is one area where we really appreciate help in implementation!

17.4. WinMerge as external compare or diff-tool

17.4.1. I want that WinMerge is closed with single ESC press after I'm done?
17.4.2. How can I avoid temporary paths filling Open-dialog history lists?
17.4.3. But program I'm using doesn't allow commandline parameters!

17.4.1. I want that WinMerge is closed with single ESC press after I'm done?

Use -e commandline switch.

17.4.2. How can I avoid temporary paths filling Open-dialog history lists?

Tell program to invoke WinMerge with the /ub option, which tells WinMerge to not add the files to the MRU.

17.4.3. But program I'm using doesn't allow commandline parameters!

Create a batch file where you add one of these lines (but not both):

  • CALL "<winmerge path>\WinMerge" /ub %1 %2
    
  • start "WinMerge" "<winmerge path>" /ub %1 %2
    

And then call this batch file from program.

17.5. Archive support

17.5.1. How can I open "Perry-style" patch files WinMerge developers use when submitting patches?
17.5.2. I do not want to install 7-zip. Can archive support use other archive tools (like WinZip or WinRar)?
17.5.3. Can WinMerge open archive files with non-standard file-extensions? (For example .jar files as zip-files)

17.5.1. How can I open "Perry-style" patch files WinMerge developers use when submitting patches?

"Perry-style" patches are zip-files containing original and changed files in different directories. WinMerge has internal support (surprise?) for handling these files. Just select zip file in question to left side and right side and WinMerge opens zip files contents to directory compare comparing original and altered files.

17.5.2. I do not want to install 7-zip. Can archive support use other archive tools (like WinZip or WinRar)?

Unfortunately WinMerge can only use 7-zip.

17.5.3. Can WinMerge open archive files with non-standard file-extensions? (For example .jar files as zip-files)

Yes, enable Detect archive type from file signature option in Archive Options.

17.6. Text encoding (codepages)

17.6.1. How do I tell if my file is coded in the local windows codepage?

17.6.1. How do I tell if my file is coded in the local windows codepage?

Open the file with Windows notepad (eg. Start->(All) Programs->Accessories->Notepad. Choose File->Save As, and in the Save As dialog which appears, look at the dropdown list at the very bottom, labelled "Encoding".

  • If it says "ANSI", the file is (apparently) in the local windows codepage. If the file is entirely in English and normal punctuation, then the file is also in ASCII.

  • If it says "Unicode", the file is (probably) in the default Windows Unicode encoding "UCS-2LE".

  • If it says "UTF-8", the file is in the cross-platform Unicode encoding "UTF-8".

  • If it says "Unicode big endian", the file is in a different Unicode encoding not much used or supported under Windows, probably "UCS-2BE".

17.7. Patch files

17.7.1. Is there way to create patch files from commandline?
17.7.2. Can patches be applied using WinMerge?

17.7.1. Is there way to create patch files from commandline?

No. It may be added in later versions but until then Win32 port of diffutils can be used. Win32 port of diffutils (and patch) can be downloaded from GnuWin32 project from SourceForge: http://sourceforge.net/projects/gnuwin32

17.7.2. Can patches be applied using WinMerge?

No. Patch tool from GnuWin32 project can be used for patch applying since WinMerge produces GNU/diffutils compatible patch files. See above question.