git post-commit hook to keep one branch updated with changes from another

post-commit

#!/bin/sh

# post-commit hook to keep one branch updated with all the changes from another
# so that the target branch always has a superset of the changes in the source branch
# do this by rebasing target off of source after each commit to source

SOURCE_BRANCH=example/generate-docs
BRANCH_TO_REBASE=task/31/models-A-D

# get the current branch in the format "* branch_name"
CURRENT_BRANCH_LINE=$(git branch | grep "*")
# get everything except the "* "
CURRENT_BRANCH_NAME=${CURRENT_BRANCH_LINE:2}

# if we're on the source branch, update the target branch with this new commit
if [ "$CURRENT_BRANCH_NAME" = "$SOURCE_BRANCH" ]; then
    echo "Updating $BRANCH_TO_REBASE with this new commit"
    echo ""

    # make sure we don't miss any commits that are only on remote
    echo "Checking for updates on remote..."
    git pull
    echo ""

    # check out the target and rebase onto the source branch
    echo "Rebasing $BRANCH_TO_REBASE off of $SOURCE_BRANCH..."
    git checkout $BRANCH_TO_REBASE
    git rebase $SOURCE_BRANCH
    echo ""

    # return to the source branch we started on
    echo "Returning to $SOURCE_BRANCH..."
    git checkout $SOURCE_BRANCH
fi