dwdiff

dwdiff is an open source command-line software that has been written to act as a front-end for the diff program, which operates at the word level and not on the line level. It’s quite different from the wdiff software, especially because it lets users to specify what exactly should be considered whitespace.

dwdiff is also capable of taking an optional list of characters, which must be considered delimiters. Furthermore, dwdiff is generally command-line compatible with the wdiff utility (except for the --autopager, --avoid-wraps and --terminal options). Thanks to dwdiff’s command-line options, users will be able to change what is printed, as well as the markers.

Command-line options

Command-line options include the ability to specify delimiters, use punctuation characters as delimiters, specify whitespace characters, read the input as the output from diff, display deleted or inserted blocks of empty lines, optionally overriding the marker.

The software can be forced to not print deleted, inserted and common words, allows users to prepend line numbers, display the number of lines of context, produce wdiff compatible output, ignore differences in case and formatting differences, as well as to use the color mode.

Among other options, we can mention the ability to allow close changes to aggregate, use bold and overstriking text, choose between best, fast and normal algorithms, use a number of words of context for matching, print statistics when the diff operation finished, and repeat markers at newlines.

Additionally, there’s an option similar to -p, but with the ability to overstrike whitespaces. Strings can be used in the software to mark the beginning and end of deleted text, as well as the beginning and end of inserted text.

Getting started with dwdiff

dwdiff is written entirely in the C programming language and distributed as a universal sources archive. It supports both 32-bit and 64-bit hardware platforms and has been reported to work on a wide range of GNU/Linux platforms.

To install it, download the latest archive from Softoware, extract it, open a terminal, navigate to the location of the extracted files, run the ‘./configure && make’ command to configure/compile the project, and then execute the ‘make install’ command as root to install it system wide.

What is new in this release:

• This release fixes the configure script in 2.0.8, which contained a typo.

What is new in version 2.0:

• This release incorporates the diff algorithm from GNU diff into dwdiff itself, removing the dependency on an external diff program. This allows dwdiff to be much faster on large files.
• When two additions were seperated by a single common word or delimiter, dwdiff would report that the common word was replaced by the two additions and the common word. This is obviously not desirable, so this has been fixed. Furthermore, when using the --diff-input option, dwdiff would sometimes report changes that spanned multiple sections from the original diff file. The new version makes this impossible.

What is new in version 1.9:

• This release adds the --diff-input option which makes dwdiff accept a Unified diff as input and reformats it using dwdiff. This option is particularly useful to reformat the diff output of version control systems.

What is new in version 1.8.1:

• The context matching now decreases the matched context size exponentially, instead of immediately using the context-less mode if the changes found with context need refining. This results in more intuitive output when increasing the matching context size.

What is new in version 1.8:

• This release adds an option to repeat the begin and end change markers at the start and end of a line, if a change crosses a newline.

What is new in version 1.5:

• The difference algorithm has been improved such that it gives better results for large changes with frequently occurring words.