prepare-commit-msg that take part of branch name

prepare-commit-msg

#!/bin/sh
#
# An example hook script to prepare the commit log message.
# Called by "git commit" with the name of the file that has the
# commit message, followed by the description of the commit
# message's source.  The hook's purpose is to edit the commit
# message file.  If the hook fails with a non-zero status,
# the commit is aborted.

#
# Converts branch name 'bugfix/APP-1234-example' and commit message 'fixed index problem' into a commit message '[APP-123] fixed index problem'
#

if [ -z "$BRANCHES_TO_SKIP" ]; then
  BRANCHES_TO_SKIP=(master develop test)
fi

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

# Seems this one is working :)
[[ $BRANCH_NAME =~ ^"APP".[0-9]* ]] && BASH_REMATCH

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

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