Git hook for appending an issue id into commit messages. The issue id is taken from branch name which should be in a "foobar-ISSUE-ID" format.

prepare-commit-msg

#!/bin/bash

regexp=".*-([A-Z].*-[0-9]*)"
branch=$(git branch | sed -n -e 's/^\* \(.*\)/\1/p')
if [[ "$branch" =~ $regexp ]]; then
    refs_id=${BASH_REMATCH[1]}
    if [ "$2" = message ]; then
        echo -ne "\n${refs_id}" >> "$1"
    else
        sed -i "1s/^$/\n\n${refs_id}/g" "$1"
    fi
fi