Add the branch name in uppercase at the beginning of your commit messages

prepare-commit-msg

#!/usr/local/bin/bash

# Instructions: Rename .git/hooks/prepare-commit-msg.sample to 
# .git/hooks/prepare-commit-msg and add the contents of this file.
# Make the file executable by typing "chmod u+x .git/hooks/prepare-commit-msg"

# This way you can customize which branches should be skipped when
# prepending commit message.
if [ -z "$BRANCHES_TO_SKIP" ]; then
  BRANCHES_TO_SKIP=(master develop test)
fi

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

BRANCH_EXCLUDED=$(printf "%s\n" "${BRANCHES_TO_SKIP[@]}" | grep -c "^$BRANCH_NAME$")
BRANCH_IN_COMMIT=$(grep -c "\[$BRANCH_NAME\]" $1)

if [ -n "$BRANCH_NAME" ] && ! [[ $BRANCH_EXCLUDED -eq 1 ]] && ! [[ $BRANCH_IN_COMMIT -ge 1 ]]; then
  sed -i.bak -e "1s/^/${BRANCH_NAME^^} /" $1
fi

Alternativ with more dynamic "branches to skip":

# prepend jira issue id to existing commit msg
# e.g. commit was done on branch story/ib-1234 with message "xy" => "IB-1234 xy"
branchPath=$(git symbolic-ref -q HEAD) # e.g. refs/heads/story/ib-1234
ticketId=${branchPath##*/} # extract text after the last /, requires bash 4
TICKET_ID=`echo $ticketId | tr a-z A-Z`

if [[ "$TICKET_ID" =~ [0-9]+$ ]]; then
printf "<$TICKET_ID> " | cat - "$1" > /tmp/outmsg && mv /tmp/outmsg "$1"
fi