Transfer git commits from one branch to another (useful for rebasing)

commit_transfer.py

#
# commit_transfer.py
#
# I wrote this script in order to transfer commits between branches in a less painful way.  The use
# case is rebasing a working branch on its parent in order to use changes that have been pushed there.
# Yes, a rebase does preserve history, but only if you haven't already pushed the branch to a remote.
# If you have, it's best to create a fresh branch from the parent and transfer the commits there.
#
# My tasks are tracked in JIRA, so I write all of my commits with the following convention:
#
#      AB-12345 Commit slug goes here
#
# I then run the following command in my old branch to grab all commits with that branch tag:
#
#      git log --oneline --grep="AB-12345" > branch.hist
#
# Any other tracking system works as long as the tag doesn't have spaces.
#
# From the new branch I run this script to cherry-pick these commits to the new branch.  It
# selects the commits in reverse order, so oldest commit first.

import subprocess

with open('branch.hist', 'r') as f:
    lines = f.readlines()
    lines.reverse()
    for line in lines:
        words = line.split()
        shah = words[0]
        branch = words[1]

        command = "git cherry-pick {}".format(shah)
        subprocess.call(command, shell=True)