udiff: Unix diff compact-mode parser🔗ℹ

1 Introduction🔗ℹ

udiff is a compact-mode diff(1) parser written in Racket.

1.1 Features🔗ℹ

• CLI tool with JSON output for easy scripting.

• Summary mode to get quick diff stats.

• Racket API to let you directly get diff output in your projects.

2 Installation🔗ℹ

Assuming you’ve already installed Racket, run the following command to install udiff.

  $ raco pkg install udiff

3 Usage examples🔗ℹ

By default, udiff expects to receive the diff output from stdin.

  $ diff -d old-file new-file | udiff | jq

Currently, udiff is specifically built to diff TSV files. It’s in my plans to broaden the diff scope and allow for more versatile usage of this tool.

4 JSON structure🔗ℹ

The JSON output returns a JSON document structured as follows.

• additions: an array of lines that only appear in the second file.

• deletions: an array of lines that only appear in the first file.

• changes: an array of objects containing both the previous (i.e. deleted) and next (i.e. added) versions of the changed row.

The object format for changes is as follows.

{

"from": "line in the first file",

"to": "line in the second file"

}