Generate a changelog from git commits

To generate a changelog from git commits, here’s a straightforward approach you can use. This process extracts commit messages and formats them into a changelog style. Below is a step-by-step guide and a sample script to automate this:

Manual Method (Basic)

Run this command in your Git repository to get a simple list of commits:

bash
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git log --pretty=format:"- %s (%h)" --no-merges

• %s — commit message subject

• %h — short commit hash

• --no-merges — exclude merge commits (optional)

This outputs a simple changelog-style list, e.g.:

pgsql
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- Fix issue with user login (a1b2c3d)
- Update README with installation steps (d4e5f6g)
- Add new feature for data export (h7i8j9k)

Automated Script for More Detailed Changelog

If you want to generate a more structured changelog (grouped by type or date), here is a sample Bash script that extracts commits since the last tag, categorizes them, and outputs a changelog.

bash
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#!/bin/bash

# Get the latest tag
LAST_TAG=$(git describe --tags --abbrev=0)

# Get commits since last tag
COMMITS=$(git log ${LAST_TAG}..HEAD --no-merges --pretty=format:"%s")

echo "## Changelog since ${LAST_TAG}"
echo ""

# You can add commit message parsing here to categorize, for example:
echo "$COMMITS" | while read -r line; do
  if [[ "$line" =~ ^feat ]]; then
    echo "- Feature: ${line#feat: }"
  elif [[ "$line" =~ ^fix ]]; then
    echo "- Bug Fix: ${line#fix: }"
  else
    echo "- Other: $line"
  fi
done

Using Tools

For professional changelog generation, consider using tools like:

• git-chglog — generates changelogs based on commit history and templates.

• standard-version — automates versioning and changelog generation based on conventional commits.

• auto-changelog — generates changelogs from git tags and commit messages.

Let me know if you want me to generate a changelog from an example commit history or if you need a script tailored to a specific commit message style!