icdiff

What icdiff is

icdiff is a free, open-source command-line tool that shows differences between two files in a side-by-side terminal view. It is intended to help reveal changes that may be hard to notice with diff, especially small edits within existing lines, rather than replace diff for every use. Users can highlight changes with foreground or background colors and customize the color map. Display options include line numbers, labels, whole-file output, whitespace highlighting, line truncation, and recursive directory comparison.

The tool supports two-way comparisons, not three-way merges, and can be used with Git, Subversion, and Mercurial. Installation methods listed by the maker include pip, apt, and Homebrew; the README also lists AUR and Nix. It runs on Linux and macOS as a command-line program that can be placed on the user's PATH. Input and output default to UTF-8, with command-line options for specifying encoding. Screen-width autodetection is Unix-only, and the exclude-lines option cannot be combined with line numbers.