Summary: Determine if two versions of the same file are the same or how they differ
Prerequisites: works on all versions; tested on all versions
Categories: Administration

Question answered by this recipe

How can I tell if two versions of the same file are the same or how they differ?


OK, this is not exactly a pmwiki recipe, but may come in handy; I know I use it a lot.

Many times when testing pmwiki and upgrading, or simply looking for bugs or differences between two versions of the same file, it's necessary to know as precisely as possible how the files differ.

Well, while we wait for the diff function of pmwiki to get better at it :), here are some alternatives:

For the Mac, there's this really neat folder/file synchronization utility, the likes of which I never found on Windoze...

  • PowerMerge le (OS9, 1996) makes not only comparisons, but backups and archiving way more secure
  • In Mac oS X there is an appli : FileMerge, too.

For Windoze systems:

  • CSDiff small, integrated in Win Explorer, displays changes in one window, it does dir as well as file comparisons (they also have HTML and XML specialized diff engines). Note: CSDiff is free, but the HTML/XML diff engine is an evaluation version with option to purchase the license.
  • CS-RCS they also released free for OpenSource developers their complete Revision Management Solution - for more serious development,
  • WinMerge displays changes in two windows side by side, both for dir anf file comparisons; a bit harder to follow (or easier if you're used with that kind of thing), and I suspect their diff engine is a bit better (can detect moved lines!); works with Unicode!!;
  • Total Commander integrated into Total Commander and features a two window, side-by-side file comparison tool as well as a comprehensive directory difference tool with ability to view file-by-file differences and manage the synchronization between them. Total Commander is free in a fully functional "nag" version -- the "nag" disappears if you purchase a license, but other than the very mild nag, the software is fully functional forever.
  • TortoiseSVN contains TortoiseMerge which does file comparison. It is integrated into explorer for folders that are part of a subversion working copy.

For Unix like systems:

  • vimdiff: edit two to four files with Vim and show differences; usually installed if you use the console (and the vim-editor); sometimes you need to update the diff if it doesn't happen automatically using :diffupdate
  • diff: compares files line by line; can recursively compare directories, but the output is not easy to read; "man diff" should explain the basic usage
  • wdiff?
  • tkdiff?
  • kdiff: for KDE users - compares and merges 2 or 3 files or directories


See Also


  • Radu March 17, 2005, at 01:46 PM
  • AKE April 26, 2006, at 8:09 AM
  • Christian
  • Balu May 11, 2006, at 10:04 AM


See discussion at CompareVersions-Talk