git hook prepare commit message for JIRA. It adds story id and story url in commit message.

prepare-commit-msg.rb

#!/usr/bin/env ruby
#
# Git prepare-commit-msg hook for JIRA project.
#
# Name your feature brach like: my-feature-STORY_ID for instance feature-LL-123
#
# Install:
# Create a file with this content in `yourproject/.githooks/prepare-commit-msg`
# or put this file somewhere, for example `~/.githooks/prepare-commit-msg`, and symlink it:
#
#     $ cd yourproject
#     $ ln -s ~/.githooks/prepare-commit-msg .git/hooks/commit-msg
#

# START configuration:
project_id = 'LL'
jira_project_url = 'https://jira.example.com/browse/'
# END of configuration


branchname = `git branch --no-color 2> /dev/null`[/^\* (.+)/, 1].to_s # get current branch name
commit_message_file = ARGV[0] # argument given by git when calling this hook
original_commit_message = File.read(commit_message_file).strip

# JIRA
jira_pattern = /(#{project_id}-\d+)/i # match branch names like my-feature-project_id-1234
if m = branchname.match(jira_pattern)
  jira_number = m.captures.first

  # Add jira_number to commit message
  message = "\n#{original_commit_message}\n\n[##{jira_number}]\nStory url: #{jira_project_url}#{jira_number}"
  File.open(commit_message_file, 'w') {|f| f.write message }
end