custom_amend.rb

#!/usr/bin/env ruby

##
# script to amend a commit which should be been created with the previous script
##

commit_message = `git log --format=%B -1`.strip
branch_name    = `git rev-parse --abbrev-ref HEAD`.strip

matches = branch_name.match (/\w\-(\d+)\Z/i)
pivotal_story_id = matches ? matches[-1] : nil

commit_message = "[##{pivotal_story_id}] #{commit_message}" if pivotal_story_id

`git commit --amend -m "#{commit_message}"`

custom_commit.rb

#!/usr/bin/env ruby

##
# script to prepend a commit with [#story-id] if the branch is suffixed with the story-id
##


commit_message = ARGV[0]

branch_name  = `git rev-parse --abbrev-ref HEAD`.strip

matches = branch_name.match (/\w\-(\d+)\Z/i)
pivotal_story_id = matches ? matches[-1] : nil

commit_message = "[##{pivotal_story_id}] #{commit_message}" if pivotal_story_id

`git commit -m "#{commit_message}"`

To explain this script:

Working on a codebase where branches are labeled "some_branch_name-123435" and 12345 is a pivotal story id.

These scripts allow me to write a commit message as I normally would, and it will then prefix each commit message so I end up with "[#12345] original comment here".