Get markdown summary of merge commits

git_cmd.sh

#!/bin/bash

function gitmd() {
  local ref="${1:-HEAD}"
  local outfile="$2"

  # Colors (terminal only)
  local BOLD="\033[1m"
  local RESET="\033[0m"
  local CYAN="\033[36m"
  local YELLOW="\033[33m"
  local GREEN="\033[32m"

  # Disable colors if exporting
  if [[ -n "$outfile" ]]; then
    BOLD=""; RESET=""; CYAN=""; YELLOW=""; GREEN=""
    : > "$outfile"
  fi

  commits_printed=0
  git log "$ref" --merges --decorate=short \
  --date=format:'%Y-%m-%d %H:%M:%S' \
  --pretty=format:'__COMMIT__%n%H%n%h%n%d%n%s%n%an%n%ad%n%ar%n%cn%n%cd%n%cr%n%p%n%b%n__END__' |
  while IFS= read -r line; do
    if [[ "$line" == "__COMMIT__" ]]; then
      read full_hash
      read short_hash
      read decorations
      decorations=$(echo "$decorations" | sed 's/^ *(//;s/)$//')
      read subject
      read author
      read author_date
      read author_date_relative
      read committer
      read committer_date
      read committer_date_relative
      read parents

      body=""
      while IFS= read -r bodyline && [[ "$bodyline" != "__END__" ]]; do
        body+="$bodyline"$'\n'
      done

      # Trim trailing empty lines
      body="$(printf "%s" "$body" | sed ':a;/^\n*$/{$d;N;ba;}')"

      commits_printed=$((commits_printed + 1))

      {
        # Header
        if [[ $commits_printed -gt 1 ]]; then
          echo -e "<br>\n"
        fi

        echo -e "# ${BOLD}**[Commit $short_hash] $subject**${RESET}"

        if [[ -n "$decorations" ]]; then
          echo -e "- ${CYAN}Refs:${RESET} ${YELLOW}$decorations${RESET}"
        fi

        echo -e "- ${CYAN}<u>**Parents:**</u>${RESET} $parents"
        echo -e "- ${CYAN}<u>**Author:**</u>${RESET} $author"
        echo -e "- ${CYAN}<u>**Author Date:**</u>${RESET} $author_date ($author_date_relative)"

        # Smarter committer display
        if [[ "$committer" != "$author" || "$committer_date" != "$author_date" ]]; then
          if [[ "$committer" != "$author" ]]; then
            echo -e "- ${CYAN}<u>**Committer:**</u>${RESET} $committer"
          fi
          if [[ "$committer_date" != "$author_date" ]]; then
            echo -e "- ${CYAN}<u>**Committer Date:**</u>${RESET} $committer_date ($committer_date_relative)"
          fi
        fi

        # Merge detection
        parent_count=$(echo "$parents" | wc -w | tr -d ' ')
        if [[ "$parent_count" -gt 1 ]]; then
          echo -e "- ${GREEN}<u>**Type:**</u>${RESET} Merge commit"
        fi

        # Summary
        summary=$(git show --stat=80 --format="" "$full_hash" | tail -n 1)
        if [[ -n "$summary" ]]; then
          echo -e "- ${GREEN}<u>**Summary:**</u>${RESET} $summary"
        fi

        # Per-file changes (git-style)
        echo ""
        echo "## Files changed:"
        echo -e "\n\`\`\`bash"
        git show --stat=80 --format="" "$full_hash" | sed '$d' | sed 's/^/  /'
        echo -e "\`\`\`"

        echo ""
        echo "## Commit message:"
        echo -e "\n\`\`\`markdown"
        echo "$body"
        echo -e "\`\`\`\n"
        echo "---"
      } | {
        if [[ -n "$outfile" ]]; then
          cat >> "$outfile"
        else
          cat
        fi
      }
    fi
  done
}