Git hook for adding branch name to commit message if it conforms to ticket naming convention

prepare-commit-msg

#!/bin/bash

# Prepend branch name to commit message in [] if matching regex. e.g. DEN-123

BRANCH_NAME=$(git symbolic-ref --short HEAD)
BRANCH_NAME="${BRANCH_NAME##*/}"

BRANCH_IN_COMMIT=$(grep -c "\[$BRANCH_NAME\]" $1)

if [ -n "$BRANCH_NAME" ] && [[ $BRANCH_NAME =~ ^([A-Z]+-[0-9]+)(\-.+)?$ ]] && ! [[ $BRANCH_IN_COMMIT -ge 1 ]]; then
    sed -i.bak -e "1s/^/[${BASH_REMATCH[1]}] /" $1
fi