A bash Git prepare-commit-msg hook to work with Git Flow and Jira style issue keys

prepare-commit-msg

#!/bin/bash +x

#The issue prefix to look for. This must be edited to match your project.
ISSUE_PREFIX=feature/ABC-

#At which line the issue should be inserted. Usually either "1" or "3".
INSERT_AT_LINE=1

#A separator which will be added after the issue is inserted. For readability.
COMMIT_TEXT_SEPARATOR=" "


#Check if it's a "fixup" or "squash" commit. If so we shouldn't alter anything.
FIRST_LINE=`head -n 1 "$1"`
if [[ x$FIRST_LINE == xfixup!* || x$FIRST_LINE == xsquash!* ]]
then
	exit
fi

BRANCH_NAME=`git symbolic-ref HEAD 2>/dev/null | cut -d"/" -f 4`
ISSUE_NAME=`echo $BRANCH_NAME | egrep -o "[A-Z]+-[0-9]+"`

if [[ x$ISSUE_NAME != x ]]
then
	#Insert any needed new lines.
	for (( i=1; i<${INSERT_AT_LINE}; i++ ))
	do
		sed -i '1i \
		' "$1"
	done
	sed -i "${INSERT_AT_LINE}i ${ISSUE_NAME}${COMMIT_TEXT_SEPARATOR}" "$1"
fi