How to improve git's diff highlighting?

Question

The output of git diff is optimized for code which tends to be one statement per line whereas text can (if authors like me are too lazy to use line breaks) caus

Answer 1

The word-diff suggested in the other answer isn't exactly what gitlab/github do. To get same effect, you can use diff-highlight script that is distributed with git.

1. First find path to diff-highlight script. It varies between systems, and is not usually in $PATH. You can find it with your package manager, for example:

   1. Fedora: rpm -ql git | grep diff-highlight
   2. Debian/Ubuntu/Mint: dpkg -L git | grep diff-highlight
   3. Archlinux: pacman -Ql git | grep diff-highlight

2. Edit ~/.gitconfig, and add to the [pager] section the following (substitute the path):

   [pager]
       # diff-highlight is script provided by git that shows word-by-word diff
       log  = perl /usr/share/git/diff-highlight/diff-highlight | less
       show = perl /usr/share/git/diff-highlight/diff-highlight | less
       diff = perl /usr/share/git/diff-highlight/diff-highlight | less
   

   I'm using perl here instead of calling the script directly because some distros, it seems, do not set executable bit on the script. IMO this is a package bug which should be reported. Anyway, this answer should work disregarding that.

Now log, diff, show commands should show difference word-by-word. Screenshot:

Answer 2

Also worth mentioning is diffr. It's written in Rust and uses Myers longest common subsequence algorithm. Compared to git's diff-highlight it gives better results, see:

git's diff-highlight:

diffr:

Once installed, making use of it is similar to that of diff-highlight, i.e. edit ~/.gitconfig, and add to the [pager] section following:

[pager]
    log  = diffr | less
    show = diffr | less
    diff = diffr | less

Answer 3

You could use the --word-diff[=<mode>] option to make it easier to see which words have changed within a line. This is described in the man page as

Show a word diff, using the <mode> to delimit changed words. By default, words are delimited by whitespace; see --word-diff-regex below. The <mode> defaults to plain, and must be one of:

• color – Highlight changed words using only colors. Implies --color.

• plain – Show words as [-removed-] and {+added+}. Makes no attempts to escape the delimiters if they appear in the input, so the output may be ambiguous.

• porcelain – Use a special line-based format intended for script consumption. Added/removed/unchanged runs are printed in the usual unified diff format, starting with a +/-/` ` character at the beginning of the line and extending to the end of the line. Newlines in the input are represented by a tilde ~ on a line of its own.

• none – Disable word diff again.

Note that despite the name of the first mode, color is used to highlight the changed parts in all modes if enabled.