script to automatically include JIRA ticket in Git commit message

git-commit-hook.sh

#!/bin/bash

# get current branch
branchName=$(git rev-parse --abbrev-ref HEAD)
branchName_uc=$(echo "${branchName}" | tr '[:lower:]' '[:upper:]')

# search jira issue id in a pattern such a "feature/ABC-123-description"
jiraId=$(echo "${branchName_uc}" | sed -nE 's/([^/]*\/)*([a-zA-Z]+-[0-9]+).*/\2/p')

# get git commit message file
commitMsgFile="$(git rev-parse --git-dir)/COMMIT_EDITMSG"

# only prepare commit message if pattern matched, jiraId was found and commit msg doesn't already have the ticket number
if [ -n "${jiraId}" ] && [ "${jiraId}" != "HEAD" ] && [ "$(grep -c "^\[${jiraId}\]" "${commitMsgFile}")" -eq 0 ]; then
  sed -i.bak -e "1s/^/\[${jiraId}\] /" "${commitMsgFile}"
fi